# British .303 vs 50 Cal M2



## pinehilljoe (Apr 17, 2018)

Were Browning M2 50s ever considered as armament for British planes? The RAF seems to have settled on .303 rifle or 20 mm cannon for armament. Reading Korda's 
*With Wings Like Eagles, *Korda credits Dowding for insisting on eight .303 minimum for the Hurricane and Spitfire. A Hurricane armed with 4 or 6 M2s would have been formidable in bringing down Heinkels.


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## buffnut453 (Apr 17, 2018)

The problem is that wing mounts for the M2 were only really perfected in late 1942. Every US fighter with wing-mounted 50cals suffered significant stoppage issues in the first 9-11 months of the war, mostly related to the ammo feed getting dislodged during aggressive manoeuvres. A fully-functioning battery of 6x50cals would, indeed, have been formidable but I don't think it was a practical proposition in 1939.

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## pinehilljoe (Apr 17, 2018)

buffnut453 said:


> The problem is that wing mounts for the M2 were only really perfected in late 1942. Every US fighter with wing-mounted 50cals suffered significant stoppage issues in the first 9-11 months of the war, mostly related to the ammo feed getting dislodged during aggressive manoeuvres. A fully-functioning battery of 6x50cals would, indeed, have been formidable but I don't think it was a practical proposition in 1939.



Other than Lend Lease, the RAF seems to have kept the 20mm or 303 to the end of the War. Was the M2 ever consider for the later Hawker fighters?


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## pinsog (Apr 17, 2018)

Weight was also an issue. 8 303’s are about 200 pounds, 4 50’s are 300 pounds. 6 50’s is around 450 pounds, and that is too much weight for pre-1943 fighters to carry. None of this includes ammo, 50 caliber ammo is about 50 pounds per 200 rounds. US 30 caliber is 33 pounds for 500 rounds (303 should be very close)


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## Shortround6 (Apr 17, 2018)

We have been over this a bunch of times.
Yes six .50 cal Brownings from 1943 using 1943 ammunition would have been a vast improvement over the eight .303 guns and ammo of 1940. 
The poor Hurricane might have struggled with the weight a bit though.
Roughly one .50 weighed as much as three .303s and the 100 rounds of .50 cal ammo weighs as much as 500 rounds of .303. 

The .50 cal of 1939-40 was not the .50 cal of 1943 however. In addition to the above mentioned wing mount feed problems the the rate of fire was lower 600rpm at best vs around 800rpm and the ammo wasn't quite the same. The M8 API round wasn't introduced until 1943, while there were both AP rounds and incendiary rounds in 1939-40 you had to mix the rounds in the belts or have one gunfire one type while another gun fired the other type. The Incendiary bullet won't pierce armor and the AP bullet won't set fire to anything.

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## pbehn (Apr 17, 2018)

Later Spitfires used 1x 0.5" gun mounted inside the cannon, in what was known as the "E" wing. I believe in the early pre war days things like security of supply played as much a part as considerations of hitting power.

The “e” wing was a further development of the Universal. It could carry either four 20mm cannon or two 20mm cannon and two 0.5in Browning machine guns. This time the cannon took the outer position and the machine guns the inner. This was partly because it gave more room for machine gun ammunition and partly because the bombs were carried below the inner gun positions, and there had been some problems reported when both cannon and bombs were on the same part of the wing. The “e” wing appeared in the second half of 1944.


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## KiwiBiggles (Apr 17, 2018)

pinehilljoe said:


> Other than Lend Lease, the RAF seems to have kept the 20mm or 303 to the end of the War. Was the M2 ever consider for the later Hawker fighters?


Why would it be? The US Navy's estimate was that the standard four 20 mm Hispanos in Hawker fighters were twice as powerful as a battery of six M2s.


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## Clayton Magnet (Apr 17, 2018)

The RAF essentially skipped the step to heavy machine guns, and standardized on cannons as soon as possible. Something that took the AAF and later the USAF about 10 more years to do.

"A Hurricane armed with 4 or 6 M2s would have been formidable in bringing down Heinkels."
Keep in mind that the standard US fighter armament in 1939/40 was one .50 supported by one or two .30's.


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## Shortround6 (Apr 17, 2018)

Clayton Magnet said:


> Keep in mind that the standard US fighter armament in 1939/40 was one .50 supported by one or *three* .30's.



Fixed it.


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## Clayton Magnet (Apr 17, 2018)

Shortround6 said:


> Fixed it.


thanks. I was thinking of the P-35, P-36 and F3F as examples


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## Glider (Apr 17, 2018)

Also remember that before the war when aircraft lacked armour and sealing tanks 8 x 303 was a formidable combination

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## J.A.W. (Apr 17, 2018)

AFAIR, the RAF determined 4 X 20mm Hispano as the 'standard fighter' fitment, ' bout 1940,
so specced 'their' Mustang with them, & regarded the Mustang III/P-51B/C fit - of 4 X 0.5in - as "light".


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## parsifal (Apr 17, 2018)

I also think that the lighter rifle caliber weapons like the 0.303 in gun allowed greater amounts of ammunition to be carried, and this favoured relatively inexperienced pilots with less ammunition and less firing time. A rookie pilot will generally start firing earlier, take longer to begin to register on the target, if at all, and against un-armoured targets of 1939 a few 303s into the target might just be enough to bring the enemy down.

Later as armour and other protection became more or less standard, a fighter with greater punch was needed. When the ammunition supplies for 20mm were increased, such that the 20mm could fire for longer than a 0.50 the equation became a no-brainer.

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## J.A.W. (Apr 17, 2018)

Pretty sure 20mm Hispano cannon ammo takes up a fair bit more space than 0.5in.
For A2G, generally gunnery 'time on target' was fairly limited so 'bursts' were more typical.

Footage of WW2 F6F's doing extended 'hosing' type firing runs on A2G was a different matter,
but AFAIR, part of the USN's reason for wanting to fit 20mm was due to those wily Nippon
infantry field engineers constructing basic tree-trunk bunkers - up to 0.5in 'proof standard'..

The 20mm Hispano would require 'an order of magnitude' - heavier protection level..


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## Shortround6 (Apr 17, 2018)

In 1940 a british 8 gun fighter was carrying about 254lbs of guns and about 160-186lbs of ammo (depending on 300 to 350 rpg to suit airplane. 2400-2800 rounds per plane)
The manual for a P-40D/E says that four .50 cal guns weigh 256lbs and 1000 round of ammo (250 per gun) weighs 300lbs.
The 6 guns on the P-40E went 384lbs with 1410 rounds of ammo (235 per gun) weighing 423lbs. 
Given the power of the Merlin III engine which do you choose?
And remember they got constant speed props fitted just in the nick of time so many of these planes would have had 2 pitch props when built.

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## J.A.W. (Apr 17, 2018)

Yes that'd be why the 'legacy' fighters, built to an ealier spec, had issues in toting 4 X 20mm.

The Hurricane had wingspace, but as SR6 noted on another thread, carried limited ammo.
The 1st Spitfires which featured 4 X 20mm - as standard, were the substantially re-designed, 1945 spec, 20-series..


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## Shortround6 (Apr 17, 2018)

Actually From the later MK Vs on they could have fitted 4 cannon if they wanted to, that was the whole idea of the "C" wing, it had the extra cannon bay built in and some MK V Spits on Malta got the 4 cannon., Insufficient gun heating and performance penalty stopped the fitting of 4 cannon until the 20 series.

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## J.A.W. (Apr 17, 2018)

Exactly, 1st gen Spits were a bit light on it..

AFAIR, Spits for Malta were fitted with quad Hispanos, but 2 of these were 'spares',
& they were not flown in combat with them..

Some Australian Mk VIII's did tote 4 X 20mm, but this was for the A2G role,
with no Nippon A2A 'trade' in prospect, to make the perfomance penalty problematic..


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## parsifal (Apr 18, 2018)

with 250 rpg of 0.5 in ammo, a gun has about 30 secs of continuous firing time. With 120 rounds per gun of 20mm ammo in belt fed versions of the weapon, there was about 1 minute of continuous firing available depending on the detail settings of the weapon. A 20mm shell does not need to hit a vital part to bring down an opponent, whereas a 0.5in still has to hit something essential

Like I said, a no brainer.


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## Shortround6 (Apr 18, 2018)

parsifal said:


> with 250 rpg of 0.5 in ammo, a gun has about 30 secs of continuous firing time. With 120 rounds per gun of 20mm ammo in belt fed versions of the weapon, there was about 1 minute of continuous firing available depending on the detail settings of the weapon. A 20mm shell does not need to hit a vital part to bring down an opponent, whereas a 0.5in still has to hit something essential
> 
> Like I said, a no brainer.


with 250 rounds 
600rpm wing mounted .50 has 25 seconds firing time
800rpm wing mounted .50 has 18.8 seconds of firing time
500rpm synchronized .50 has 30 seconds firing time.
with 120 rounds
600rpm Hispano has 12 seconds. 
with 300 rounds
a 1100rpm .303 had 16.4 seconds Adjust for Hurricane and Spit MK II & later. 

The .50 ( and Russian 12.7mm) had wider range of possible targets in an aircraft than the .303 (or anybodies rifle caliber machine gun) because it could do more damage to the structure. 
Holes right through structural components rather than gouges. Some BP tanks were good against rifle caliber fire but not against bigger holes. The .50 could cause seams to rupture on fuel tanks depending on size and how full they were. It could penetrate more armor (it could also fail spectacularly if the bullet hit something before the armor).
There were plenty of spaces on an aircraft where the .50 is going to go right through and just make a slightly bigger hole than the RCMG. But with the .50 things like longerons, spars, ribs, engine mounts and the like are much more likely to suffer major damage.
Now everything I just said about the .50 gets multiplied for the Hispano 20mm even if the Hispano is firing ball ammo (non exploding) or the fuse fails to function. 

BTW the weights I gave earlier for the British .303 and the American .50 are a bit skewed. The .303 weights are from a weights and loading chart for a Spitfire and may very well represent the .303 s as installed. many charts/descriptions use a lighter weight. 
The weight for the .50s, on the other hand, are about as light as I have ever seen. Early F4F with four guns and 200rpg has a weight of 524.5lbs. 
Things like gun heaters, charging/cocking systems and even firing solenoids are sometimes counted and sometimes not.

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## swampyankee (Apr 18, 2018)

pinehilljoe said:


> Other than Lend Lease, the RAF seems to have kept the 20mm or 303 to the end of the War. Was the M2 ever consider for the later Hawker fighters?



The RAF looked at 0.5 in MG before WWII, but found the advantages of this bore insufficient compensation for heavier weight and lower rate of fire (RAFHS 08). I suspect this similar to at least part of the reason for the USAAF staying with the 0.5 in until it was found insufficient during Korea: the 0.5 in was successful in WWII, and the 20 mm was heavier with a lower rate of fire. No doubt, the failure of US industry to make the 20 mm aircraft gun successfully was a further discouragement.

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## fastmongrel (Apr 18, 2018)

Theres also the fact that many RAF pilots in 1940 could have been flying aircraft armed with Laser equipped Sharks and they still wouldnt have shot anything down.


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## Shortround6 (Apr 18, 2018)

We have been over this more than once. By Korea the .50 cal was the M-3 and firing at 1200rpm or close. A roughly 50% increase over the mid to late war guns and a 100 % increase over the pre-war guns. The main round had also changed from the M8API to the M-23 Incendiary'

The M-23 was a much lighter bullet with a MV of 3400fps and carried 5.8 grams of incendiary material compared to the 2.2 grams in the M2 incediary and the 1 gram in the M8 API. 

It still wasn't enough but the AIr Force did NOT go into Korea with WW II armament thinking it was good enough.

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## swampyankee (Apr 18, 2018)

Shortround6 said:


> We have been over this more than once. By Korea the .50 cal was the M-3 and firing at 1200rpm or close. A roughly 50% increase over the mid to late war guns and a 100 % increase over the pre-war guns. The main round had also changed from the M8API to the M-23 Incendiary'
> 
> The M-23 was a much lighter bullet with a MV of 3400fps and carried 5.8 grams of incendiary material compared to the 2.2 grams in the M2 incediary and the 1 gram in the M8 API.
> 
> It still wasn't enough but the AIr Force did NOT go into Korea with WW II armament thinking it was good enough.



But they did go into Korea with 0.5 in guns, albeit improved, on the basis they’d be good enough, even though everyone else had concluded they weren’t


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## swampyankee (Apr 18, 2018)

fastmongrel said:


> Theres also the fact that many RAF pilots in 1940 could have been flying aircraft armed with Laser equipped Sharks and they still wouldnt have shot anything down.



And those flying with the German, Japanese, American, etc. air forces.

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## buffnut453 (Apr 18, 2018)

I thought the Germans actually developed laser-equipped sharks...and they were absolute world-beaters. They could fly for 12,000 miles on a thimble-full of the distilled fat left over from cooking bratwurst. The lasers were gyro-stabilized and calculated environmental offsets to a level that was an order of magnitude better than the Norden bomb sight...plus they could burn through any armour AND used skin-friction dielectric cells to generate the necessary power, thus enabling the equipment to be installed in an aircraft.

In fact, the only thing in the German inventory that was better than the laser-equipped sharks was the Fw-187.

Yeah..I know. Coat time. AGAIN!!!

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## swampyankee (Apr 18, 2018)

buffnut453 said:


> I thought the Germans actually developed laser-equipped sharks...and they were absolute world-beaters. They could fly for 12,000 miles on a thimble-full of the distilled fat left over from cooking bratwurst. The lasers were gyro-stabilized and calculated environmental offsets to a level that was an order of magnitude better than the Norden bomb sight...plus they could burn through any armour AND used skin-friction dielectric cells to generate the necessary power, thus enabling the equipment to be installed in an aircraft.
> 
> In fact, the only thing in the German inventory that was better than the laser-equipped sharks was the Fw-187.
> 
> Yeah..I know. Coat time. AGAIN!!!




Their _experten_ were so good, they only needed one shot to shoot down two airplanes (three on the Eastern Front)


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## J.A.W. (Apr 18, 2018)

Shortround6 said:


> We have been over this more than once. By Korea the .50 cal was the M-3 and firing at 1200rpm or close. A roughly 50% increase over the mid to late war guns and a 100 % increase over the pre-war guns. The main round had also changed from the M8API to the M-23 Incendiary'
> 
> The M-23 was a much lighter bullet with a MV of 3400fps and carried 5.8 grams of incendiary material compared to the 2.2 grams in the M2 incediary and the 1 gram in the M8 API.
> 
> It still wasn't enough but the AIr Force did NOT go into Korea with WW II armament thinking it was good enough.




Were these upgraded 50cal HMG's only fitted to the gleaming new F-86's or was there a retro-fit program
in-theatre to extend this advantage - to the older types doing A2G, as well?

I recall reading memoire by dual WW 2/Korea US fighter pilots where they'd remarked on both the number of rounds
the improved 6-gun fit could project, & the ++ amount of hits the more robustly constucted fighter-jet MiGs, took to down.


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## parsifal (Apr 18, 2018)

I found this which may be of interst:

Sorting Out the “E” – American Armament for the Spitfire Mk. IX/XVI — Variants & Technology | Spitfire Mk. IX | Spitfire Mk. XVI


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## Clayton Magnet (Apr 19, 2018)

Excellent article, thank you! 
Makes me wonder though, was the Mk.5 Hispano ever fit to the Spitfire? Seems like it would have made more sense than fitting M2 machine guns in the cannon bay.


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## Walrus (Apr 19, 2018)

fastmongrel said:


> Theres also the fact that many RAF pilots in 1940 could have been flying aircraft armed with Laser equipped Sharks and they still wouldnt have shot anything down.



I'm sure that most RAF pilots in 1940 were more accurate than your wild disrespectful shooting off of the mouth.


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## pbehn (Apr 19, 2018)

parsifal said:


> I found this which may be of interst:
> 
> Sorting Out the “E” – American Armament for the Spitfire Mk. IX/XVI — Variants & Technology | Spitfire Mk. IX | Spitfire Mk. XVI


Interesting comment to the article posted by ex forum member Edgar Brooks, Rest in peace Edgar.

Papers, in the National Archive, at Kew, give a few answers to the queries. The XVI, as a Mark no., did not exist until August, 1944, when it was realised that separate listings, for spares, etc., were needed, and the Air Ministry finally unbent, and acceded to the requests for a new Mark. Since other Marks had been introduced into production, in the meantime, it explains the wide gulf between the numbers. It’s also the reason why it’s impossible to find mention of the XVI any earlier; L.F.IX was the usual designation, whatever the engine.
All low-back aircraft had to have the “E” armament, since the planned fuel tanks, behind the pilot, entailed the relocation of the compressed-air bottles, which went into the no.3 Browning’s compartment; at the same time the extra fuel meant longer flight times, so three oxygen bottles became necessary, two of which went into the no.4 gun compartments.
Another reason for the delay in the introduction of the XVI/low-back XIV was the reluctance of the Air Ministry to replace 4 x .303″ with 2 x .5″; it was found that, from the rear, the .5″ had no extra penetrative power over the .303″, and the general (lack of) shooting ability, by the average pilot, meant that the hosepipe effect of four guns, in a deflection shot, had a better chance of disabling the enemy pilot.
The arrival of the gyro gunsight changed all that, since the pilots’ aim improved beyond all measure, so the A.M. finally went for the “E” wing. There was a further delay to the low-backs, though, since the electrical boxes, for the G.G.S., had to be installed before the fuel tanks, otherwise the tanks would need removal, for the sight to go in. All of this is the reason why the low-backs did not see service until 1945.

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## Walrus (Apr 19, 2018)

AFAIK there was a strategic decision made by the Ministry of Defence to standardise munitions to .303 calibre.
Presumably this was to help ease of production and logistics. 

x2 0.50 Brownings were equipped in some bomber turrets to improve defensive fire, replacing x4 .303 mgs
RAF Mustangs were armed with x4 0.50 mgs (except the MkI which were armed with 20mm cannon iirc) and IIRC some Spitfire wings included 0.5s with 20mm cannon


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## pbehn (Apr 19, 2018)

Clayton Magnet said:


> Excellent article, thank you!
> Makes me wonder though, was the Mk.5 Hispano ever fit to the Spitfire? Seems like it would have made more sense than fitting M2 machine guns in the cannon bay.


In addition to the article posted by Parsival, there were many issues with Spitfire wings firstly it was so thin it was difficult to heat the outer guns and Cannon were a bit of a problem when cold. 

Also this from the History of War website.
"The “e” wing was a further development of the Universal. It could carry either four 20mm cannon or two 20mm cannon and two 0.5in Browning machine guns. This time the cannon took the outer position and the machine guns the inner. This was partly because it gave more room for machine gun ammunition and partly because the bombs were carried below the inner gun positions, and there had been some problems reported when both cannon and bombs were on the same part of the wing. The “e” wing appeared in the second half of 1944."


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## Shortround6 (Apr 19, 2018)

I would recommend this site for information about the British use/manufacture/purchase of .50 cal ammo along with every other British round of under 20mm.
.50 inch Browning - British Military Small Arms Ammo
British Military Small Arms Ammo

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## David Fred (Apr 19, 2018)

pinehilljoe said:


> Were Browning M2 50s ever considered as armament for British planes? The RAF seems to have settled on .303 rifle or 20 mm cannon for armament. Reading Korda's
> *With Wings Like Eagles, *Korda credits Dowding for insisting on eight .303 minimum for the Hurricane and Spitfire. A Hurricane armed with 4 or 6 M2s would have been formidable in bringing down Heinkels.


The E wing Spitfires, notably the Mk XIVe which appeared 2Q1944, and the Mk IXe which appeared in 4Q1943 had on had on M2 and one 20mm Hispano per Wing were produced, but I don’t know in what quantities. Source: Fighter Aircraft Performance Of WW2- A Comparative Study by Erik Pilawskii


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## Clayton Magnet (Apr 19, 2018)

besides using wikipedia, what was the difference in weight between a Mk.5 Hispano and M2 Browning?


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## Glider (Apr 19, 2018)

Clayton Magnet said:


> Excellent article, thank you!
> Makes me wonder though, was the Mk.5 Hispano ever fit to the Spitfire? Seems like it would have made more sense than fitting M2 machine guns in the cannon bay.


The fittings for the Mk V 20mm were exactly the same as the Mk II 20mm so they certainly could be fitted and the Seafire was normally equipped with the Mk V


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## David Fred (Apr 19, 2018)

Clayton Magnet said:


> besides using wikipedia, what was the difference in weight between a Mk.5 Hispano and M2 Browning?


I have another book, the “bible of WW2 aircraft armament, called “Flying Guns, WW II” by Anthony G.Williams, and Dr. Emmanuel Gustin.
On Page 331 of Appendix 6, it states the Browning M2, using a 12.7 x 99 cartridge weighed 29 kilos. The 20mm Hispano II weighed 50 kilos, and the Hispano V, both using the 20 x110 cartridge, weighed 42 kilos. All are empty weights.
For comparison, the 30mm Mk 108 used on the Me-262, besides having the ballistics characteristics of a bowling ball, and very limited ammo, weighed 60 kilos.


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## Greyman (Apr 19, 2018)

Clayton Magnet said:


> besides using wikipedia, what was the difference in weight between a Mk.5 Hispano and M2 Browning?



Figures and references from an RAE report concerning aircraft gun armament during the war:

Weight of gun complete
Hispano II (109 lb) - A.P. 1641F
Hispano V (75 lb) - A.P. 1641F
Browning M2 (53 lb) - Colt Handbook Section IIIB

EDIT: more detailed information for the Browning from:

TM 9-225 (1942)
Browning .50 M2 Aircraft (fixed) - 61.4 lb

A.P. 1641L (1949)
M.G.532 or M2 (fixed) / No.1, Mk.II - 64 to 68 lb


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## David Fred (Apr 19, 2018)

Clayton Magnet said:


> besides using wikipedia, what was the difference in weight between a Mk.5 Hispano and M2 Browning?



Here’s the comparison between the 20mm Hispano and the Mk108 30 x 99.Note that only 1/3 of the 30mm is propellant. Muzzle velocity is only 550 m/s, which means a 5 meter drop at 550 meters. Plus, the plane had 100 rounds per gun firvthe bottom two, and 80 founds per gun for the top two.

This is an interesting (if crappy) cannon. In order to increase rate of fire from about 410 rpm to 600, instead of mounting the recoil spring around the barrel like a Bofors, they put it _behind the bolt_. To prevent a release of explosive gases in the fuselage, it had a very short barrel, (44cm) hence the lower muzzle velocity.


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## David Fred (Apr 19, 2018)

David Fred said:


> View attachment 490423
> 
> 
> Here’s the comparison between the 20mm Hispano and the Mk108 30 x 99.Note that only 1/3 of the 30mm is propellant. Muzzle velocity is only 550 m/s, which means a 5 meter drop at 550 meters. Plus, the plane had 100 rounds per gun firvthe bottom two, and 80 founds per gun for the top two.
> ...





One other thing I did, using the book I mentioned, and another called “Who Won the Battle of Britain” by Wing Commander H.R. Allen. I put it in a spreadsheet, because in 40 years I still can’t build a table in Microsoft Word.
It’s in the top table.
Below is the cartridge photos of the 20mm and the 30mm. Sorry, I’m new at this.

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## pbehn (Apr 20, 2018)

David Fred said:


> View attachment 490424
> View attachment 490424
> 
> 
> ...


Great post David, basically it shows why the RAF switched from 8 x rifle (sometimes 12) 0.303 calibre mgs to 20mm cannon in 1940/41, and why the P-51 upped from 4 to 6 guns between the B/C and the D version.

BTW I always used to construct tables in Exel and paste them into Word.


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## Shortround6 (Apr 20, 2018)

I am not understanding some of the tables.
Rate of fire isn't making sense as labeled. rate of fire for the number of guns over how many seconds?
Energy at impact at what range or impact velocity?
Energy at impact for how many projectiles? 

BTW the velocity for the .303 is incorrect, Velocity was between 2400 and 2500fps for most service rounds used in WW II.


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## tomo pauk (Apr 20, 2018)

David Fred said:


> Here’s the comparison between the 20mm Hispano and the Mk108 30 x 99.Note that only 1/3 of the 30mm is propellant. Muzzle velocity is only 550 m/s, which means a 5 meter drop at 550 meters. Plus, the plane had 100 rounds per gun firvthe bottom two, and 80 founds per gun for the top two.
> 
> This is an interesting (if crappy) cannon. In order to increase rate of fire from about 410 rpm to 600, instead of mounting the recoil spring around the barrel like a Bofors, they put it _behind the bolt_. To prevent a release of explosive gases in the fuselage, it had a very short barrel, (44cm) hence the lower muzzle velocity.



MK 108 was a very good cannon, throwing good-sized HE shells at good rate of fire, while being lightweight for all or that.
A reason why the MK 108 have had low MV was that propellant charge was of light weight when compared with weight of the shell. What version of the MK 108 was with 410 rds/min?


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## David Fred (Apr 20, 2018)

pbehn said:


> Great post Fred, basically it shows why the RAF switched from 8 x rifle (sometimes 12) 0.303 calibre mgs to 20mm cannon in 1940/41, and why the P-51 upped from 4 to 6 guns between the B/C and the D version.
> 
> BTW I always used to construct tables in Exel and paste them into Word.



Thanks. Now that I am getting on a bit, I find the time to buy and read these specialist books, and this is a good one, not cheap, and supposedly in “layman’s terms” (layman what I can’t imagine).


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## pbehn (Apr 20, 2018)

David Fred said:


> Thanks. Now that I am getting on a bit, I find the time to buy and read these specialist books, and this is a good one, not cheap, and supposedly in “layman’s terms” (layman what I can’t imagine).


It just seems an odd comparison because they are different eras. If there were any 8 x 0.303 armed Spitfires or Hurricanes flying in 1944 they weren't being used as fighters. You could also compare the firepower of the Mustang Mk I with 4 x 20mm cannon ordered in 1940 with P-51B/C with 4 x 0.5" mgs since these were operational in the same era.


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## David Fred (Apr 20, 2018)

tomo pauk said:


> MK 108 was a very good cannon, throwing good-sized HE shells at good rate of fire, while being lightweight for all or that.
> A reason why the MK 108 have had low MV was that propellant charge was of light weight when compared with weight of the shell. What version of the MK 108 was with 410 rds/min?



There was none. The author points out that a longer barreled version with a conventional Bofors type recoil spring and without Advanced Primer Ignition would have had higher MV but lower rate of fire. The projectile had 83 grams of explosive in Mk 108, a substantial load, useful against slow moving bombers, but a fighter speeds, withe the trajectory of a drop of 1.225 meters at 250 meters, and 4.9 meters at 550 meters, adjusting aim in fast moving combat against maneuvering fighters would have been nearly impossible. In fact, I can find no record of a fighter being downed by this weapon, and on hit would have been enough.
The Germans called it the “pneumatic hammer”, because of the the “thunk, thunk, thunk” it made when fired.


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## David Fred (Apr 20, 2018)

pbehn said:


> It just seems an odd comparison because they are different eras. If there were any 8 x 0.303 armed Spitfires or Hurricanes flying in 1944 they weren't being used as fighters. You could also compare the firepower of the Mustang Mk I with 4 x 20mm cannon ordered in 1940 with P-51B/C with 4 x 0.5" mgs since these were operational in the same era.



I built the table years ago when someone asked, not on this forum, what if the MkI Spitfire had used M2’s instead of 1919’s


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## Graeme (Apr 21, 2018)

Part of an article by Roy Braybrook. Air International September 1985...


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## Greyman (Apr 21, 2018)

Graeme said:


> Part of an article by Roy Braybrook. Air International September 1985...



_"It was cheap, readily available, fully developed ..."_
In the mid 30s when they would have needed to make a decision? I would argue no.

_"It is a fair bet that the Air Staff rejected this option on the ground that 'If this is what the Americans are doing, it is almost certainly wrong'._
Citation needed on that one. Where's that eyeroll emoji?

_"The irony of the situation was that Luftwaffe aircraft never were armoured against 0.50-in ammunition."_
I think he would be surprised at the effect of passing through several feet of aircraft structure would have on a .50 bullet.


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## Shortround6 (Apr 21, 2018)

Well,
1. in error on fully developed. 
2. in error on weight
3. in error on rate of fire in time for the BoB
4. Early ammo and in fact early WW II British ammo, used a lower velocity than the the Newly introduced US M2 loadings. British were buying ammo with 1500fps velocity in 1940 and after instead of getting the 2800-2900fps loadings. 
Once again see : .50 inch Browning - British Military Small Arms Ammo

"
Britain was aware of this development and first considered use of the Browning in late 1918 to counter German ground attack aircraft that were fitted with armour too thick for the .303 inch Armour piercing ammunition to defeat. As the war ended, British interest in the .50 inch Browning lapsed for several years.

Further trials took place in 1923 and 1924 with ammunition supplied by Kynoch to compare performance with the newly developed .5 inch Vickers ammunition and in the period 1924 - 26 Woolwich both reloaded American cases with their own design of bullet and manufactured complete rounds. Kynoch also supplied flame tracer ammunition."

and 
"*"Cartridge S.A. Armour Piercing .50 inch Browning W Mark Iz" *was the American M1 AP round and included the Remington made contract ammunition. Britain purchased .50 inch ammunition both from the American government (via the U.S. Steel Corporation) and on contract from Remington for the RAF, some of which was specially marked to British requirements. Large quantities were also supplied under Lend Lease."
"The bullet had a gilding metal envelope with a hardened steel core and a lead tip filler with no sleeve. Weight was about 750 grains."
"Muzzle velocity was 2,500 fps with a charge of about 240 grains of nitrocellulose propellant and penetration was 1/2 inch of armour at 1,000 yards."


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## tomo pauk (Apr 21, 2018)

David Fred said:


> There was none. The author points out that a longer barreled version with a conventional Bofors type recoil spring and without Advanced Primer Ignition would have had higher MV but lower rate of fire.



Hmm - then why specifying the rate of fire of 410 rds/min at the 1st place? How much higher the MV would've been if the working principe was not the API blowback? Since when the API blowback is equivalent of high RoF and low MV anyway?
The MK 108 have had 30g of propellant, the MK 101/103 112g, both for the Mine shell. So unless the ammo for the MK 108 is helped by fairy dust or unicorn breath, the MV will still remain as it was with the 330 g M-shell.



> The projectile had 83 grams of explosive in Mk 108, a substantial load, useful against slow moving bombers, but a fighter speeds, withe the trajectory of a drop of 1.225 meters at 250 meters, and 4.9 meters at 550 meters, adjusting aim in fast moving combat against maneuvering fighters would have been nearly impossible. In fact, I can find no record of a fighter being downed by this weapon, and on hit would have been enough.



Re. no record found on MK 108 downing a fighter - how many late-war German records have you read? 
That drop on distance - is it for sea level, 10000 ft, 25000 ft? 
Interestingly enough, Germans themselves were of opinion that MK 108 is a viable weapon even for the targets doing 700 km/h.



> The Germans called it the “pneumatic hammer”, because of the the “thunk, thunk, thunk” it made when fired.



That is probably how the Allied crews called it.


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## swampyankee (Apr 21, 2018)

tomo pauk said:


> Hmm - then why specifying the rate of fire of 410 rds/min at the 1st place? How much higher the MV would've been if the working principe was not the API blowback? Since when the API blowback is equivalent of high RoF and low MV anyway?
> The MK 108 have had 30g of propellant, the MK 101/103 112g, both for the Mine shell. So unless the ammo for the MK 108 is helped by fairy dust or unicorn breath, the MV will still remain as it was with the 330 g M-shell.
> 
> 
> ...




With a muzzle velocity of 550 m/s, a drop of 5 m in 550 m horizontal distance assumes vacuum.


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## Shortround6 (Apr 21, 2018)

The "drop" is a rather overused and almost useless way of comparing aircraft guns.

Drop is dependent on time of flight. Whatever distance your projectile covers in 1 second, that is the distance at which it will "drop" 4.78 meters.
Distance covered in 1 second goes increases with altitude as the air gets thinner.

Now as to why it is near useless, fighter guns were not set dead level in the plane. sighting chart for a P-47




Guns were pointed slightly upwards to cross the line of sight and then fall back down to the line of sight.
Now this is good example of one extreme, guns almost 4 feet below the line of sight/sight line and guns with a high velocity/slow velocity decay.

The German 20mm mine shell and the 30mm mine shell are the other extreme but the 30mm is not quite as bad as portrayed in many online accounts as it is seldom compared to the other common German guns/projectiles

A 109 has the guns much closer to the line of sight but then it doesn't really matter if the projectiles go 10-15 inches above the line of sight instead of only 6-9 inches. You can get the downward crossing of the line of sight out to a useful distance. The idea that the poor pilot was having to compute "drop" at combat ranges of 200-500 meters is rubbish. Once the bank goes past 45 degrees then drop may enter into it but trying to figure a few feet of drop compared to how many plane lengths ahead you need to be shooting in minor.

They were trying to compute lead on the moving target and in this short flight times was definite advantage.
However, Flight time for a 30mm HEI 330gram projectile with a MV of 500m/s to 600 meters was 1.66 seconds. The 92gram 20mm mine shell from a MG/FFM took 1.428 seconds. These are at ground level. 

AS to Tomo's question;


tomo pauk said:


> Since when the API blowback is equivalent of high RoF and low MV anyway?



It all depends on how the gun was set up. You could get decent rate of fire (but not great) and high velocity as the Japanese showed with the Type 99-2.

But API blowback guns are rather sensitive to ammo and especially so if you are trying for light weight.
In order to get the rate of fire up (and the weight down) on the MK 108 they used a light breechblock which meant the breechblock started moving to the rear quickly, more quickly than a heavier a breech block. SO quickly that the base of the cartridge was coming out of the chamber before the projectile left the muzzle and the unsupported sidewall of the case would blow out letting high pressure gas into the action and gun compartment. With a short barrel the projectile cleared the barrel, the gas pressure vented through the open muzzle and no more blown cases.
guns like the Hispano use a combination action. They use a mechanical lock to hold the bolt closed until the projectile reaches a certain point in the barrel at which point the mechanism unlocks and the residual pressure in the chamber/cartridge cases, pushes the breech block back and extracts/ejects the case.
At the cost of some weight/complication this allows for a much lighter breech block/mainspring to be used to get the rate of fire up.

On the MK 108, once they got to a certain point in the design/development they were stuck. They can't make the barrel longer without suffering from the blown out cases, unless they use a heavier breechbock and/or main spring. Heavier breech block means heavier gun and lower rate of fire. Stronger mainspring/buffer might mean slower opening but faster closing, effect on rate of fire is????? however faster closing means more battering on the gun parts and for a gun designed to be built of stampings and lower grade steel that may not be a good option.

As I said, the API method of action is not mutually exclusive from high rate of fire and high MV (look at 20mm Oerlikon guns as used by the Americans and British, ballistic twin to the Hispano but it sure isn't lighter


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## tomo pauk (Apr 21, 2018)

Thanks for the feedback, people.

This is how the Germans rated two weapon options for the Me 262 - one comprises from 2 x MK 103 and 2 x MG 151/15 (= migh MV), other is the historical set-up with 4 x MK 108 (= 'low' MV). The effect on target of 10 HE shells of the MG 151/15 is judged to be equal to one hit of the 3 cm M-shell. Hit percentages and time-to-hit with 'normal' Revi, with EZ 42 sight and conclusion:


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## David Fred (Apr 21, 2018)

Greyman said:


> _"It was cheap, readily available, fully developed ..."_
> In the mid 30s when they would have needed to make a decision? I would argue no.
> 
> _"It is a fair bet that the Air Staff rejected this option on the ground that 'If this is what the Americans are doing, it is almost certainly wrong'._
> ...



Thanks. I think the cannon was well suited for bomber work, but I like the .50 “hail of lead” against inline engines or the light Japanese aircraft


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## Barrett (Apr 21, 2018)

Sidebar:
Long (long) ago when I didn't have a lot to do, I crunched the numbers on AAF fighter armament effectiveness, deriving the credited kills as a % of all claims (probables-damaged.)
Guess what?

Four .50s was optimum for WW II fighters; anything more was excess baggage.
The P-51D had 50% more firepower than the B/C at a gain of only 10% in lethality.

Little known: the upgunned F4F-4 was done at request of the Brits who wanted more punch against German/Italian aeroplanes. But the extra "throw weight" was offset by reduced ammo & therefore trigger time. I asked some Wildcat exponents about that, and got the same response from most (Joe Foss, Swede Vejtasa, George Wrenn, etc): "I saved two guns as get me home insurance."

The FM-2 "Wilder Wildcat" reverted to four guns and did extremely well--in fact, it had by far & away the best kill-loss ratio of any WW II fighter I know of, on the order of 30-1. (Largely reflective of the CVE mission.)


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## Shortround6 (Apr 21, 2018)

Barrett said:


> Four .50s was optimum for WW II fighters; anything more was excess baggage.
> The P-51D had 50% more firepower than the B/C at a gain of only 10% in lethality.
> 
> Little known: the upgunned F4F-4 was done at request of the Brits who wanted more punch against German/Italian aeroplanes. But the extra "throw weight" was offset by reduced ammo & therefore trigger time. I asked some Wildcat exponents about that, and got the same response from most (Joe Foss, Swede Vejtasa, George Wrenn, etc): "I saved two guns as get me home insurance."
> ...



And again we are back to _who_ was ordering _ what, when._ 

IF the British were ordering Wildcats _before _the US got the rate of fire of the M-2 up to 800rpm then the six gun armament certainly makes sense.
60 rounds per second vs the 40 rounds per second of the four guns. Once the M-2 got to 800 rpm you had about 53-54 bullets per second but didn't have the extra weight. 

IF the British were ordering in 1940 they were planning on ammo having a MV of 2500fps. I don't know exactly when the US changed to the M2 loading over the M1 but the British were ordering M1 equivalent ammo in 1940-41, The US had changed a bit earlier but I don't know when. 

The Mustang "B"s and the FM-2 used M8API ammo (as did just about everything else from 1943 on) Almost the entire belt was the M8 armor piercing incendiary round. In 1941-42 the belts used various mixtures of AP and Incendiary ammo at best, at worst there was a certain amount of ball ammo included. Add tracer to suit  

What I don't know (aside from the M8 ammo which was too late) is how much the rate of fire and the change in MV may have affected (or not affected) the British choice to go with six guns.

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## Shortround6 (Apr 21, 2018)

Getting back to the original subject a British 8 gun fighter in 1940 could put out about 150-160 bullets per second. 
If we assume 1140 rounds per per barrel (19 rounds per second) and a weight of 174 grains per bullet we get a weight of* 3.77lb* per second of metal being put in the air. Adjust rate of fire as you see fit.

For the .50 cal option we have 4 guns firing at 600rpm or 40 bullets a second total, each bullet (ball or AP) is 750 grains (British spec) so we get a weight of
*4.28lb* of metal in the air per second. 

Now the British .303 ammo was about 2440fps for Ball (which was fired out of about 3 guns of the eight in the BoB) and 2500fps for the AP with the tracer and incendiary pretty much falling right in line. British spec for .50 cal ammo in 1940 was for 2500fps muzzle velocity.

This means at close range down low or even a few hundred yds range at altitude there wasn't much to choose in velocity of impact between the two and therefore the impact energy will pretty much follow the weight of metal. Granted each hit will penetrate deeper or cause more damage on substantial parts. Hitson skin over voids will call for pretty much the same fabric or metal patch. 

The .50 cal in British service will not show a big difference in deflection shooting either with the initial velocities being so close. 
Granted as the range opens the Advantage will show up more but as the range opens the deflection problem gets considerable worse for both guns.

Please note this is for 1940 and the BOB. By 1942 things were changing for both guns, greater scale of issue of AP and incendiary for the. 303 
Slightly lighter but much higher velocity bullets for the .50 and the higher rate of fire.

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## David Fred (Apr 21, 2018)

David Fred said:


> Thanks. Now that I am getting on a bit, I find the time to buy and read these specialist books, and this is a good one, not cheap, and supposedly in “layman’s terms” (layman what I can’t imagine).



From the same book, this photo from a WW2 secret diagram of a Mk1 Spitfire hit probability against an He-111.

The dotted lines represent that 100% of rounds landed within that area, the solid lines, 70%..

Top to bottom, 100, 200, 300, and 400 yards, with the guns harmonized at 350 yards.

Also, elsewhere in the book they mention that dispersion increased greatly in a hard turning, high G fight, because the Spitfire thin wing was subject to torsional effects, which had less effect on the inboard Guns, but quite a lot on the outboard guns.

In fact, as you read below, from “Fighter Aircraft Performance Of WW2: A Comparative Guide”, by Erik Pilawskii.

It speaks to why so many pilots who had flown both the Hurricane and Spitfire praise the Hurricane as a “more stable gun platform.”

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## David Fred (Apr 21, 2018)

Shortround6 said:


> I am not understanding some of the tables.
> Rate of fire isn't making sense as labeled. rate of fire for the number of guns over how many seconds?
> Energy at impact at what range or impact velocity?
> Energy at impact for how many projectiles?
> ...


Rate of fire in combat bursts, primary source Wing Commander H.R. Allen, DFC, from his book, “Who won the Battle of Britain”, where he cites studies done by the RAE. The rest of the data is from the same source, but extrapolated, because as Allen points out, the studies were done early, when comparing 6 .303 Guns with 4 M2’s.

If you want more about methodology, but Allen’s book. I can’t photocopy 6 pages here.


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## fastmongrel (Apr 22, 2018)

Walrus said:


> I'm sure that most RAF pilots in 1940 were more accurate than your wild disrespectful shooting off of the mouth.



Do some research before posting and you will find that most RAF pilots in Aug/Sept 1940 had very poor shooting skills.

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## pbehn (Apr 22, 2018)

fastmongrel said:


> Do some research before posting and you will find that most RAF pilots in Aug/Sept 1940 had very poor shooting skills.


Some threads on this forum are useful.
RAF Pilot Training in WW2
RAF Pilot Training Hours 1940

However it wasn't just RAF pilots in 1940 it was all pilots, the gyro gunsight improved marksmanship in all services that used it.

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## Zipper730 (Apr 22, 2018)

From what I remember, the RAF had considered fitting the 0.50 to the bombers, but the arrival of the USAAF prevented that for some reason


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## MycroftHolmes (Apr 23, 2018)

fastmongrel said:


> Do some research before posting and you will find that most RAF pilots in Aug/Sept 1940 had very poor shooting skills.



Pbehn has got in first, but the great majority of pilots in all air forces were poor marksmen, for the simple reason that aerial gunnery is very difficult. The difference was that the RAF looked at the performance of its pilots with a cold and objective eye and realised that they weren't doing very well, so they thought about how to improve matters and produced the gyro-gunsight. By contrast, the Luftwaffe/USAAF/USN were rather smug and complacent and simply assumed that all was well. If you believe otherwise, you are implying that British pilots are somehow genetically incapable of good shooting, since the RAF certainly spent considerable time and effort on gunnery, including deflection-shooting.


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## pbehn (Apr 23, 2018)

MycroftHolmes said:


> Pbehn has got in first, but the great majority of pilots in all air forces were poor marksmen, for the simple reason that aerial gunnery is very difficult. The difference was that the RAF looked at the performance of its pilots with a cold and objective eye and realised that they weren't doing very well, so they thought about how to improve matters and produced the gyro-gunsight. By contrast, the Luftwaffe/USAAF/USN were rather smug and complacent and simply assumed that all was well. If you believe otherwise, you are implying that British pilots are somehow genetically incapable of good shooting, since the RAF certainly spent considerable time and effort on gunnery, including deflection-shooting.


The summer of 1940 was a desperate time, pilots were not trained long enough in any skill let alone gunnery which was done in many cases at OTUs. The gyro gun sight was being worked on before the war started with the first version in production in 1941.


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## Shortround6 (Apr 23, 2018)

The subject of air to air gunnery (as opposed to the subject of the guns) is a woefully under studied one.
I don't believe that any nations (people) were any better or any worse shots than any other.
What differed was _Instruction_ and _Practice_. The _Quality_ of both and the _Time_ spent on both. These varied considerably throughout war in just about every Air Force (or every Air Force?). Let alone from air force to air force. 

For example For the US you had John Thach, " graduated from the United States Naval Academy in 1927 and spent two years serving in battleships, before becoming a Naval Aviator in early 1930.[2] Thach spent the next decade serving as a test pilot and instructor and establishing a reputation as an expert in aerial gunnery"

another source says that during part of that time he was a gunnery instructor. Please note that he had been flying for 12 years at the time of Midway.

"In the early 1940s, he was placed in command of Fighting Squadron Three (VF-3). There he met a young ensign just out of flight school, Edward O'Hare, later a Medal of Honor recipient. Thach made O'Hare his wingman and taught him everything he knew. At the U.S. Navy fleet gunnery competition at the end of 1940, eight of the 16 VF-3 pilots qualified for the gunnery "E" award ("excellence")"

See: Butch O'Hare and the Thach Weave | U.S. Naval Institute
For an interesting story about Thach and Butch O'Hare.

Unfortunately for the british, it seems to an outsider, that too much of the 30s was spent on NEW theories (no allowance shooting/turrets, aiming fixed guns in multiple directions) ) and not enough on getting the most out of what they had. Gunnery training _seems _to have been done on once a year (?) _camps _where the squadrons left their home fields and operated out of the gunnery (or bombing) field/base for one or two weeks. I could be wrong about this but this is hardly the way to reach high standards of proficiency. I would note that Thach was probably an exception to the rule of how the USN was operating/training at the time. 

The Boffins can invent all the fancy sights they want (not to disparage the Boffins, better equipment is always useful) but if time is not given to training and practice then the improvements in equipment are never up to what they could be.

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## Clayton Magnet (Apr 23, 2018)

David Fred said:


> Thanks. I think the cannon was well suited for bomber work, but I like the .50 “hail of lead” against inline engines or the light Japanese aircraft


Then wouldn't 8x 303 be even more effective? far more projectiles in the air, far better percentage for a critical hit.
But simply punching holes was determined to be insufficient. Whether an aircraft was liquid cooled or air cooled largely didn't matter, the best way to destroy either one was to hit it with explosive cannon shells. 
There is an interesting love affair with the M2 .50, and its effectiveness is always exaggerated as an air to air weapon. It could certainly BE effective, but history shows that cannons were the way forward.


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## pbehn (Apr 23, 2018)

During the BoB the British had experience of literally hundreds of bullets hitting a bomber without bringing it down. Perhaps there is more psychology. The British were having to bring down bombers over the UK and wanted to do it as quickly as possible, not knowing what will come next. Since the RAF had new bombers on order it would be reasonable to expect the LW did too.


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## fastmongrel (Apr 23, 2018)

pbehn said:


> The British were having to bring down bombers over the UK



Many in the RAF believed that shooting down Bombers was less important than breaking up the main bomber force and preventing a cohesive force dropping all their bombs on target.


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## pbehn (Apr 23, 2018)

fastmongrel said:


> Many in the RAF believed that shooting down Bombers was less important than breaking up the main bomber force and preventing a cohesive force dropping all their bombs on target.


Well it is a valid discussion, if their target is your airfield or plane factory stopping a successful attack is probably more important than the number of bombers shot down, a different calculation when a city is being attacked.


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## fastmongrel (Apr 23, 2018)

pbehn said:


> Well it is a valid discussion, if their target is your airfield or plane factory stopping a successful attack is probably more important than the number of bombers shot down, a different calculation when a city is being attacked.



The early attacks were targeted even if it was a large area like London Docks. I think targetting cities came later with the Night Blitz.


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## pbehn (Apr 23, 2018)

fastmongrel said:


> The early attacks were targeted even if it was a large area like London Docks. I think targetting cities came later with the Night Blitz.


There were many facets to the discussion, for example Dowding was frustrated by pilots mobbing one damaged bomber eventually bringing it down. He considered it much better to damage many than down a few. Park and Dowdings policy of meeting every attack with something meant there were very few "free hits" with bombers being completely undisturbed, when they did they could cause serious damage.

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## Greyman (Apr 23, 2018)

MycroftHolmes said:


> By contrast, the Luftwaffe/USAAF/USN were rather smug and complacent and simply assumed that all was well.



I think that's a mischaracterization of the other nations' efforts. They were on the case - the other countries were just out-boffin'd by the Brits.

And props are due to the French who had the first two successful gyro gunsights (Alkan-Genin type and LMS type). They took two people in a Potez 630 to operate - but hell, they got about 30% hits on Heinkel-sized targets over 500m away.

There was also a Schneider-Fieux sight the French had in the works that turned out to be on a similar path as the British Gyro sight in October 1939.




Clayton Magnet said:


> Then wouldn't 8x 303 be even more effective? far more projectiles in the air, far better percentage for a critical hit.



In Burma/India the Hurricane IIb squadrons were even removing four of their 12 guns because they found eight .303 guns sufficient and the little extra performance would be worth it.


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## pinsog (Apr 23, 2018)

Greyman said:


> In Burma/India the Hurricane IIb squadrons were even removing four of their 12 guns because they found eight .303 guns sufficient and the little extra performance would be worth it.



They were removing guns because they were desperate, the Hurricane was inferior to the Japanese opposition



pbehn said:


> There were many facets to the discussion, for example Dowding was frustrated by pilots mobbing one damaged bomber eventually bringing it down. He considered it much better to damage many than down a few.



I can't imagine this line of thinking. If you have 10 rats on your doorstep and you just run them off with a broom, tomorrow there will be 10 rats back on your doorstep. If you obliterate 1 rat with a 12 gauge shotgun, tomorrow there will only be 9 rats. Same thing applies to bombers attacking your cities.



Clayton Magnet said:


> Then wouldn't 8x 303 be even more effective? far more projectiles in the air, far better percentage for a critical hit.
> But simply punching holes was determined to be insufficient. Whether an aircraft was liquid cooled or air cooled largely didn't matter, the best way to destroy either one was to hit it with explosive cannon shells.
> There is an interesting love affair with the M2 .50, and its effectiveness is always exaggerated as an air to air weapon. It could certainly BE effective, but history shows that cannons were the way forward



There is not that much space inside a WW2 combat aircraft that is simply open space for bullets to pass harmlessly through aside from maybe the outer wings. The wings held weapons, ammo, fuel, control cables and linkage aside from structural wing spars and such. The body obviously held the engine, pilot, fuel, control linkage etc. If you aim to hit center mass where the wing and body join, you should be hitting the pilot, fuel tanks etc.

Not sure what country you live in, but have you ever seen or held a 30-06 and a 50 BMG together? There is a huge difference in what a 150 grain and a 750 grain bullet look like and what damage they will do. Self sealing fuel tanks were generally very effective against rifle caliber fire while a single 50 could actually burst the tank at the seems. Many pilots were wounded by rifle caliber machine-gun fire, flew home, recovered and fought again since a 150 grain 30 caliber bullet would lose so much energy after passing through some aircraft structure. A 50 on the other hand, is a whole different ballgame. Unless you have true armor plate behind you, a 50 could pass through some significant structure, tumble sideways and still have plenty of power left to gut you like a fish. A 50 also has the mass/power to damage/sever lager aircraft structure like wing spars.

Some of you gentlemen who have served in the armed forces and used the 50 on targets such as old trucks etc should chime in with what you have seen it do.


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## Shortround6 (Apr 23, 2018)

Sights were going through a rapid evolution at this time also.








Some countries were using an "optical sight" sometimes called telescopic. 








These actually offered little or no magnification. 
What they did do was place the aiming mark and target in the same focal plane (they would appear to be the same distance from the pilots eye making it easier to focus). They gave bit more leeway to where the pilots eye could actually be without affecting the point of impact like the ring and bead. And the pilot now had to only line up two things. The aiming mark and the target. With the ring and bead he had to line up the target, the front part of the ring and bead and the rear part. 
Please note there is NOTHING to help the pilot estimate range with with ether set up or to assist in any way with defection shooting except the pilots experience. 

More in next post

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## Clayton Magnet (Apr 23, 2018)

pinsog said:


> Some of you gentlemen who have served in the armed forces and used the 50 on targets such as old trucks etc should chime in with what you have seen it do.


Now compare the effect of an explosive 20mm projectile. 
This was caused by 3 hits from a Oerlikon, and the aircraft was scrapped as a result.


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## pbehn (Apr 23, 2018)

pinsog said:


> I can't imagine this line of thinking. If you have 10 rats on your doorstep and you just run them off with a broom, tomorrow there will be 10 rats back on your doorstep. If you obliterate 1 rat with a 12 gauge shotgun, tomorrow there will only be 9 rats. Same thing applies to bombers attacking your cities.
> .


This was provoked by as many as seven pilots making joint claims for one enemy aircraft. There is a sound logic to it. If an aircraft is damaged over London, it still has a long way to fly back and land. Examination of post war records showed a lot of bombers landed but were effectively written off , ditched in the channel or made a crash landing. It was in a way a side effect of the "Big Wing" when you have a wing of 50 aircraft all together in a small area they completely outnumber the attacking bombers even if the total number of bombers was in the hundreds.


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## pinsog (Apr 23, 2018)

Impressive damage from 3 rounds. I would never argue round for round damage with 20mm vs 50. I would like to point out that this is a Spitfire (not reputed to be the toughest fighter of the war) and yet it still flew home, pilot landed safely, pilot lived to fight another day and plane was probably scrapped because they had more available not because it wasn't repairable. It also proves the point that, like hunting, where you hit them is many times more important than what you hit them with (within reason). If that group had been 12 feet farther forward, that Spitfire wouldn't have made it home.


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## pinsog (Apr 23, 2018)

pbehn said:


> This was provoked by as many as seven pilots making joint claims for one enemy aircraft. There is a sound logic to it. If an aircraft is damaged over London, it still has a long way to fly back and land. Examination of post war records showed a lot of bombers landed but were effectively written off , ditched in the channel or made a crash landing. It was in a way a side effect of the "Big Wing" when you have a wing of 50 aircraft all together in a small area they completely outnumber the attacking bombers even if the total number of bombers was in the hundreds.



I can see their thinking in a way, but a trained fighter pilot or bomber crew is harder to replace than the machine itself. But, I can also see the logic in breaking up a formation and limiting target damage by attacking/damaging many bombers vs killing just a few and the bombers succeed in damaging/destroying their target.

Like almost any subject it is rarely a right/wrong or black/white issue

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## Shortround6 (Apr 23, 2018)

Many people were going to reflector type sights.





Aiming mark is projected onto the clear (somewhat) screen giving pilot wider field of view than the "optical" sight. 
This model has two adjustments. One to "set the range" and the other to set the size of the aircraft. 
I believe (but welcome correction) that the bottom dial (base) was set to the wingspan (or length ) of the target aircraft and the top dial was set to the desired range of engagement. When the target's wing span touched the sides of the circle the target was at the range set. 

While much better than previous sights, this still required the pilot to input the correct settings and to "judge" when the wingtips were touching the circle on both sides and to _estimate _the range if the target was not square on to the sight and to _estimate _the amount of hold off or lead needed if firing from anything but a 6 o'clock or 12 o'clock position. Again very dependent on pilot experience/expertise.
The Gyro sight could figure out deflection shooting but did not become available in general until 1944 despite prototypes/proof of concept flying much earlier. 
AND they needed to 'track' the target for a short period of time to give correct solution. I believe they could also be rendered unusable (at least for a time) by violent maneuvers or inverted flying? Could very well be wrong on this one. 

None of these sights are going to give good results to the vast majority of pilots if they only got a few "days" of gunnery practice before going into combat. A day might only consist of a few target runs per day after ever squadron member got his turn and scores were counted/posted. 
It was common for bullets to be dyed or painted to give an indication as to which plane fired them once the target was on the ground and could be inspected. 
However getting feedback from target impact a 1/2 hour to several hours after doing the shooting sure hinders quick learning.

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## pinsog (Apr 23, 2018)

They say "The 20mm is 3 times more effective than the 50"

Question: What does that mean?

1. Does it mean 3 50 bullets do the same damage as 1 20mm?
If so, then a fighter with 4 50's and 450 rpg would have the same amount of killing power as a fighter with 4 20mm and 150 rpg it would just take longer

2. Does it mean it takes 3 times longer for a 50 to bring down an aircraft? (It takes a 2 second burst from 4 20mm to bring down an ME110 so it takes 6 seconds for 4 50's) If so, then rate of fire of each individual weapon would come into play

3. Does it mean by weight of weapons and ammo carried? (800 pounds of 20mm cannon and ammo is 3 times more effective than 800 pounds of 50 BMG machine guns and ammo)


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## Clayton Magnet (Apr 23, 2018)

pinsog said:


> It also proves the point that, like hunting, where you hit them is many times more important than what you hit them with (within reason). If that group had been 12 feet farther forward, that Spitfire wouldn't have made it home.


The fact that it made it home is extraordinary. The spitfire had a stressed skin construction, so the skin itself was load bearing. The advantage of the explosive shell, is that is kinda DOESN'T matter where it hits. I suspect that aircraft was a hair's breadth away from shedding its entire empennage, or large section of its aft skin. If you can separate an aircraft from its parts, it will go down very quickly.


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## pinsog (Apr 23, 2018)

_View: https://www.youtube.com/watch?v=yzzDaOfbPZA_


youtube video of weapons fired at 48 gallon water barrel including a 308 (very close to 303) 338 Lapua and 50 BMG. Notice how 50 completely ruptures the barrel.


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## Shortround6 (Apr 23, 2018)

It is a very rough approximation as there are a crap load of variables.

I would note that I Believe that this comparison is for the 20mm Hispano and the .50 cal Browning *ONLY, * as changing to different 20mm guns.diffrent 12.7-13.2mm machine guns changes a crap load more variables.

I believe the original comparison was for "muzzle horsepower". A somewhat interesting but totally useless metric for comparing guns in the real world.

Muzzle HP is the foot pounds of energy generated per minute (or second) by the weight of the projectiles times their velocity squared and the rest of the kinetic energy formula. Please note this takes no account of the target effects of HE shells, of which the US .50 used NONE. 

The big problem with the .50 was more theoretical. It was certainly effective in batteries of 4-8 guns as used in US fighters on the targets US fighters had to deal with. 
The problem is one of efficiency. the guns and ammo are heavy for the target effect you get. If you have big enough engines (and airplanes) you can stuff enough .50 cal guns in them to get the job done (at least the job/s the US needed doeing). If the US had had smaller or lower powered engines then things might have gotten a bit more iffy.


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## Clayton Magnet (Apr 23, 2018)

Shortround6 said:


> If the US had had smaller or lower powered engines then things might have gotten a bit more iffy.


Or faced formations of heavy bombers


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## pinsog (Apr 23, 2018)

Clayton Magnet said:


> The fact that it made it home is extraordinary. The spitfire had a stressed skin construction, so the skin itself was load bearing. The advantage of the explosive shell, is that is kinda DOESN'T matter where it hits. I suspect that aircraft was a hair's breadth away from shedding its entire empennage, or large section of its aft skin. If you can separate an aircraft from its parts, it will go down very quickly.



That could explain why the Spitfire didn't do as well against the Zero as the Wildcat. In The First Team, one of the Wildcats on Guadalcanal took 20 20mm hits including one that burst inside the gas tank and the Wildcat flew home and was 'repaired' (spit, bubblegum, bailing wire, hope and prayers) well enough to fight again.


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## Shortround6 (Apr 23, 2018)

Or that yes, 



Shortround6 said:


> at least the job/s the US needed doeing


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## pinsog (Apr 23, 2018)

Shortround6 said:


> It is a very rough approximation as there are a crap load of variables.
> 
> I would note that I Believe that this comparison is for the 20mm Hispano and the .50 cal Browning *ONLY, * as changing to different 20mm guns.diffrent 12.7-13.2mm machine guns changes a crap load more variables.
> 
> ...



I agree the comparison was between 20mm Hispano and Browning 50.
Agree that 'muzzle energy' is a horrible way of comparing firearms.
Agree with last paragraph.
Agree with the post below yours saying heavy bombers might have been a problem, although, it would have been interesting to see how well a P47 with 8 50s faired against B17 and B24's.

In Korea, didn't the USAF intercept a group of Soviet TU-4 bombers (B29 copies) and decimate them? Wouldn't they have all had 50's?


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## Clayton Magnet (Apr 23, 2018)

pinsog said:


> it would have been interesting to see how well a P47 with 8 50s faired against B17 and B24's.


a P-47 armed with 4 Hispano's would have probably weighed less, with significantly greater firepower. Although I am assuming on both points


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## pinsog (Apr 23, 2018)

Clayton Magnet said:


> a P-47 armed with 4 Hispano's would have probably weighed less, with significantly greater firepower. Although I am assuming on both points



Give Shortround a few minutes and he will list the weights for everything! 
The later P47's with the paddle prop and water injection could probably have hauled 6 Hispano's into the air along with the ammo and still maintained high performance at altitude. But as it has been pointed out, it simply didn't have any enemies big enough to justify that armament


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## Shortround6 (Apr 23, 2018)

pinsog said:


> I agree the comparison was between 20mm Hispano and Browning 50.
> Agree that 'muzzle energy' is a horrible way of comparing firearms.
> Agree with last paragraph.
> Agree with the post below yours saying heavy bombers might have been a problem, although, it would have been interesting to see how well a P47 with 8 50s faired against B17 and B24's.
> ...



AN F-86 in Korea had M-3 guns (as did F-84s) firing at about 1200rpm so equal to about 9 WW II .cal guns. They also were using incendiary ammo with much more incendiary filler, The F-86 also had a small radar rangefinder in the upper lip of the intake that fed into the gyro gun sight. Not sure about the F-84. 

If the intercept was done by piston powered planes then they may well have had the slower firing guns. I don't think (but could be wrong) that the P-51s were retrofitted. P-80s are iffy either way.


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## Greyman (Apr 23, 2018)

pinsog said:


> They were removing guns because they were desperate, the Hurricane was inferior to the Japanese opposition



Not so much inferior as requiring a less intuitive fighting style in order to be successful. Same as the Flying Tigers and their Tomahawks.

Wing Commander Ops Paul Richey (yes that Paul Richey), AHQ Bengal:
_The Japanese fighters have their good and bad points, our own fighters have their good and bad points. A comparison of the Japanese Army 01 and the British Hurricane makes it obvious from the start that in a certain type of fighting the Japs should come off best. This is borne out by experience: the Japs can dog-fight better than we can: however, they are lightly armed and need to get in good long bursts against our heavily armoured aircraft before they can shoot them down. Their manoeuvrability enabled them to do this if we try to dog-fight them. On the other hand, one short accurate burst from a Hurricane usually causes the disintegration of an 01 - and the Hurricane is faster. All this being so, the obvious thing to do is to work out tactics to give ourselves the maximum advantage. We won't dog-fight. We will only attack from above, diving and firing a short burst before climbing again. If we are caught out and below the Japs or at their level we will immediately take steps to reverse this situation by diving away and climbing up again before attacking. We will defeat the Japs by cleverness._

Where the Hurricane was most inferior was with respect to the Spitfire, not the Japanese aircraft. The main issue in India/Burma was actually making successful interceptions of Japanese formations, not desperation once combat was joined.

A bit from Sgt Yoshido Yasuda of the 64th Sentai:
_The Hurricane was a unique plane with twelve 7.7 mm machine guns which caused deadly damage if we were shot from behind. Its diving speed was much faster than the 01 Fighter. Therefore, when we fought with Hurricanes we attempted to counter its firepower with the better manoeuvrability of the 01 and tried to hit its radiator, bringing the engine to a stop. Even with the poor firepower of the 01, Hurricanes could be shot down merely by a hole in the radiator._

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## swampyankee (Apr 23, 2018)

pinsog said:


> They say "The 20mm is 3 times more effective than the 50"
> 
> Question: What does that mean?
> 
> ...




I believe it's the first.


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## Greyman (Apr 23, 2018)

Shortround6 said:


> I believe (but welcome correction) that the bottom dial (base) was set to the wingspan (or length ) of the target aircraft and the top dial was set to the desired range of engagement. When the target's wing span touched the sides of the circle the target was at the range set.
> 
> ...
> 
> AND they needed to 'track' the target for a short period of time to give correct solution. I believe they could also be rendered unusable (at least for a time) by violent maneuvers or inverted flying? Could very well be wrong on this one.



The circle didn't change, but the gap within the horizontal bar changed depending on the settings.

re: the Gyro sight becoming unusuable - the sight's gyro will be thrown against the stops if deflections too large for the sight are pulled. This can be prevented by keeping the sight 'caged' (set to minimum range) then adding range to the sight and 'closing down' the graticule as you track the target. Dogfighting with the sight set to 800 yards will cause trouble.

I haven't come across anything about issues with inverted flight.


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## Shortround6 (Apr 23, 2018)

Thank you.

I would call the adjustable gap in the bar more of a range indicator than range finder but any help to prevent pilots from opening fire at 3 to 4 times the desired range would be a help.


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## Greyman (Apr 23, 2018)

Almost like you wrote the manual. 

*Range-estimating mechanism,*
23. The purpose of the range-estimating mechanism is to obviate any tendency to open fire while still out of effective range; it is not intended to function as a range finder in the accepted sense.​


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## fastmongrel (Apr 24, 2018)

I wonder if the RAF ever had films made or posters printed showing the sizes of various aircraft at the correct firing range ie a Heinkel 111 will look this big in the sight at 300 yards and a Dornier 17 wil look this big and so on. You can read time and time again where gun camera films were checked and the inexperienced pliots were opening fire at ranges up to and even sometimes over 1,000yards.


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## pbehn (Apr 24, 2018)

fastmongrel said:


> I wonder if the RAF ever had films made or posters printed showing the sizes of various aircraft at the correct firing range ie a Heinkel 111 will look this big in the sight at 300 yards and a Dornier 17 wil look this big and so on. You can read time and time again where gun camera films were checked and the inexperienced pliots were opening fire at ranges up to and even sometimes over 1,000yards.


They did, and that is (I believe) why they worked on gun sights and gyro gun sights because I think they sussed out that in the heat of a dog fight pilots needed aids to help them to do what they actually knew they should do. The gyro gun sight had a great effect on the accuracy of USAAF pilots who had a different scheme of training but in the end had the same problem.


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## soulezoo (Apr 25, 2018)

Shortround6 said:


> AN F-86 in Korea had M-3 guns (as did F-84s) firing at about 1200rpm so equal to about 9 WW II .cal guns. They also were using incendiary ammo with much more incendiary filler, The F-86 also had a small radar rangefinder in the upper lip of the intake that fed into the gyro gun sight. Not sure about the F-84.
> 
> If the intercept was done by piston powered planes then they may well have had the slower firing guns. I don't think (but could be wrong) that the P-51s were retrofitted. P-80s are iffy either way.


A reminder that P-47N's (Iwo Shima?) were fitted with M-3's toward the end of the war. 8 M-3's, I imagine, could put some hurt on a bomber of any size.


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## KiwiBiggles (Apr 25, 2018)

soulezoo said:


> A reminder that P-47N's (Iwo Shima?) were fitted with M-3's toward the end of the war. 8 M-3's, I imagine, could put some hurt on a bomber of any size.


Not really, no more than the Hurricane IIB (12 x 0.303) was deadlier to German bombers than the Hurricane I. Simply throwing more undersized rounds at a target doesn't really add much.


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## Greyman (Apr 25, 2018)

For what it's worth the Brits and Canadians both judged the value of the CF-100's eight centreline M3s as 'doubtful' (re: Bull, Bosun, Badger, Bison).


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## Shortround6 (Apr 25, 2018)

Even .303s don't "bounce" off.
Their ability to break large objects (wing spars for instance) is certainly limited but most engines that catch a 1/2 dozen or more .303 bullets are going to stop running after a few minutes. At least if the.303s are being feed proper ammo. No iron engine blocks on most aircraft engines (some Wright engines use steel crankcases) so at the very least you have coolant or oil leaks. Not to mention hits to "accessories" are not good.

The American .50 is an odd weapon in WW II, it was about the only weapon of it's size and weight that did *not* use HE ammo or even high capacity incendiary ammo. They _started _with incendiary available but phase it out when they adopted the M8 API round. Then they tried again with the really capacity M23 (or what would turn into the M23) but that ammo was highly unreliable (Drgondog's father seems to have had some tales about it lighting up right in front of the firing aircraft?). It probably depended more on kinetic energy than just about any other gun (only the Russian 12.7mm is in the same area and the Russians may have had better incendiary ammunition?) 

The .303 in the BoB gets a bad rap for three things that were not it's fault.
1. The poor shooting in general of the British pilots.
2. The Air Ministries attempt/s to solve the first problem by pointing the guns in different directions so instead of concentrating at one distance and being spread at others it was spread at all distances.
3. An ammo shortage that had, at times, 3 guns out of 8 firing "ball" ammo intended for rifles or ground machine guns instead of AP or incendiary ammo.


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## Shortround6 (Apr 25, 2018)

Greyman said:


> For what it's worth the Brits and Canadians both judged the value of the CF-100's eight centreline M3s as 'doubtful' (re: Bull, Bosun, Badger, Bison).



When you get to jet bombers things take another change. The airframe and wing/fuselage skins you need to fly at 500mph are whole lot thicker/heavier than the ones needed for 300mph airplanes. 

The two small Russian bombers weigh empty close to what a B-17E did empty. (the IL-2 is about 4,000lbs less) but the wings are about 1/2 the size, the Tu-14 has about the same length fuselage but the IL-28 is 16ft shorter, The VK-1 turbojet while heavy was certainly much lighter than two R-1820s. 
This is empty weight so it had to go somewhere. Heavier stronger structure?


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## Greyman (Apr 25, 2018)

Shortround6 said:


> Even .303s don't "bounce" off.
> Their ability to break large objects (wing spars for instance) is certainly limited but most engines that catch a 1/2 dozen or more .303 bullets are going to stop running after a few minutes. At least if the.303s are being feed proper ammo. No iron engine blocks on most aircraft engines (some Wright engines use steel crankcases) so at the very least you have coolant or oil leaks. Not to mention hits to "accessories" are not good.



I think when pilots report rounds 'bouncing off' enemy aircraft it's probably due to striking the skin at very shallow angles and deflecting off.

Dowding himself considered it very fortunate that the Germans never armoured the rear of their bombers' engines - so that area with its 'mass of ancillary equipment' always remained vulnerable.



Shortround6 said:


> The .303 in the BoB gets a bad rap for three things that were not it's fault.
> 1. The poor shooting in general of the British pilots.
> 2. The Air Ministries attempt/s to solve the first problem by pointing the guns in different directions so instead of concentrating at one distance and being spread at others it was spread at all distances.
> 3. An ammo shortage that had, at times, 3 guns out of 8 firing "ball" ammo intended for rifles or ground machine guns instead of AP or incendiary ammo.



2. The big 'Dowding Spread/Horizontal Pattern' business was called off in Feb 1940 - so the battle was fought with the 'Concentrated Pattern'. The not-so-big 'Spread Pattern' came into effect mid-'42.

3. I think the ball rounds at this time were more by design than shortage. Dowding claiming that in tests the AP round was more easily deflected.

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## Shortround6 (Apr 25, 2018)

As far as 3 goes, that may depend on the test and the desired result or secondary target? Perhaps the AP did deflect more often but was the "ball" ammo (and was it MK VII or MK VIIIz ) with it's lead core going to have much penetration of a secondary target if it hit sideways? The "hardness" of many components once you got under the skin varied quite a bit. On some the ball ammo may have worked fine, on others perhaps the AP would have been better.
The AP was rated this way "For proof, 70% of bullets had to penetrate a 10mm plate at 100 yards range." which means that each production batch is going to have some cartridges taken out at random and fired to make sure the batch/lot was up to specification. Granted there is no intermediate barrier like an aircraft skin to tip the bullets before they hit the plate. Test firing was also done on the ground so velocity at impact will be bit higher at 100yds or more importantly, will retain velocity better at higher altitudes. 
Later Spitfires carried two guns loaded with AP and 2 guns with Incendiary MK VI.
During the BoB it was reported that they used 3 guns with ball, 2 with AP, with incendiary/tracer MK IV and one gun with the Incendiary MK VI.
The incendiary/tracer MK IV carried 6 grains of white phosphorus and pretty much ignited on leaving the barrel. The longer it took to reach the target the less incendiary effect you were going to have. The Incendiary MK VI used 7 grains of SR 365 containing barium nitrate and did not burn in flight but bullets that broke up on the exterior of the plane would give a visible flash which was quite useful as a hit indicator. 

A further note from Anthony Williams' book is that while they had decided in March (close enough to Feb) to use concentrated fire there was still dispute over the distance, Some squadrons using 350 yds and some 250yds. Dowding decided on 250yds in March but apparently not all squadrons changed as combat reports from June of 1940 showed the 53% success rate for the shorter distance vs 39% for the longer one. no mention of how "success" was measured. 
decisions could be made high-up, how fast they were implemented by all squadrons might be different.


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## Greyman (Apr 26, 2018)

Shortround6 said:


> A further note from Anthony Williams' book is that while they had decided in March (close enough to Feb) to use concentrated fire there was still dispute over the distance, Some squadrons using 350 yds and some 250yds. Dowding decided on 250yds in March but apparently not all squadrons changed as combat reports from June of 1940 showed the 53% success rate for the shorter distance vs 39% for the longer one. no mention of how "success" was measured.
> decisions could be made high-up, how fast they were implemented by all squadrons might be different.



Dowdings orders were issued 23 Feb, so March is a good bet for implementation as well.

I have a copy of the June '40 report in question and it deals with the Horizontal Pattern (60 ft. wide box at 400 yards) vs. the Concentrated Pattern (single point at 250 yards) during the period 16 Oct '39 and 10 Apr '40. 

Success was a bomber 'known to have been destroyed'.

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## Shortround6 (Apr 26, 2018)

Thank you for that information.


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## slaterat (Apr 28, 2018)

I have the complete Hurricane II manual with the loading data.
Hurricane IIa 8x .303
guns and accessories 201 lbs, ammunition and boxes, 204 lbs = 405 lbs
Hurricane IIc 4 x20mm
guns and accessories 427 lbs, ammunition and boxes, 327 lbs = 754 lbs

additional info
1 x 20mm gun with firing unit 106.25, 100 rounds of 20 mm ammunition 62.5 lbs
1 .303 browning gun with release and safety units, 24 lbs, 100 rounds of .303 6.63 lbs

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## Juha2 (Apr 29, 2018)

pinsog said:


> I ...In Korea, didn't the USAF intercept a group of Soviet TU-4 bombers (B29 copies) and decimate them? Wouldn't they have all had 50's?



IIRC Tu-2s twin-engine medium bombers, not Tu-4s. IMHO very improbable that Tu-4s would have flown in Korean airspace during the war. And yes the US fighters participating the action were armed with .5s


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## ChrisMcD (Apr 29, 2018)

To get back to the original question. I had a feeling that we had answered this before. To quote Vanir in 2011
"Some comments on this by Sqn Ldr Ralph Sorley, FO1 of the Air Ministry in evaluation of fighter armament proposals for service use new British monoplane fighters (Spit and Hurri) in 1934.
(paraphrasing for space and clarity) "The choice lay between the .303 gun, the 0.50 gun and a new 20mm Hispano cannon. Of the .303 guns the result was the Browning from American Colt company appeared to offer the best possibilities. Given the numbers of stockpiled Vickers, the acceptance of a new gun in the numbers required was a heavy financial and manufacturing commitment. During 1934 the Hispano gun is experimental and confirmed details about its performance are hard to establish. The 0.50 on the other had had been developed little (in 1934) and although it possessed better hitting power it was a slow firing and heavy item together with its ammunition. A trial on the ground of eight .303 guns was sufficiently convincing and satisfying to carry the day."
.50 cal machine guns vs 20 mm autocannons on US aircraft

I am not totally convinced. It does seem that the RAF were happy to stick with the .303 because they were convinced by the late 30's that the 20mm cannon was the way to go.
This is a link to Colin Sinnott's book on Google books that may work!
The RAF and Aircraft Design, 1923-1939

It seems to indicate that all the RAF bigwigs in the late 30's were determined to get the maximum number of bullets fired in 2 seconds rather than worry about the "weight of shot".
Personnally, I think that they should have persevered with the 0.5 over the .303


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## Glider (Apr 29, 2018)

From what I know the basic we will stick with 8 x 303 which was a very powerful battery in 1939, until the 20mm is fixed was the right approach. It came a little unstuck when the 20mm took longer to get right than first thought, but it was in my mind the correct approach.
It tends to be overlooked that the USN were very keen to supplement the 0.5 with the 20mm but it took the US until almost the end of the war to sort out the debacle that they made of the 20mm.

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## Shortround6 (Apr 29, 2018)

ChrisMcD said:


> To get back to the original question. I had a feeling that we had answered this before. To quote Vanir in 2011
> 
> I am not totally convinced. It does seem that the RAF were happy to stick with the .303 because they were convinced by the late 30's that the 20mm cannon was the way to go.
> 
> ...



The thing was that the small Browning was pretty much ready to go. The British did modify to fire open bolt to prevent cooking off rounds with cordite propellent and no doubt would have had to do the same thing with the .50 cal. 
Ammo for the .303 was pretty much a done deal, Ball, AP, tracer all existed along with a few specialty items (drill, proof rounds etc) although no one was very happy with the tracer/incendiary. 
For the .50 things weren't so cut and dried. There was US ammo but it hadn't been "approved" by the British. Also please note, as has been mentioned before, that US .50 cal ammo in the 20s and 30s had muzzle velocity of about 2500fps. It took a change in propellent to give it the higher velocity that the US used in WW II.

In fact the US .50 cal cartridge had no velocity advantage to speak of over the British/Vickers .5 in machine gun cartridge, it did use heavier bullets. 

For perspective here are the muzzle energies of the four rounds. 

.303 AP, 174 grain bullet at 2500fps..................2415 ft lbs.
.5 Vickers AP, 580 grain bullet at 2540fps...........8308 ft lbs.
.50 cal AP M1, 750 grain bullet at 2500fps.........10408 ft lbs.
.50 cal AP M2, 710 grain bullet at 2810fps.........12447 ft lbs.

Now the .303 Browning fired just about twice as fast as the .50 cal Browning until some time in 1940. And the big .50 went just about 3 times the weight. 

So the British would have had to "persevered" with the .50 by developing higher velocity ammo a the same time the Americans were and also increased the rate of fire of the gun and increased the belt pull. 

How much engineering time to you devote to a gun and ammo that the British would only use (on fighters) as an interim gun until they could get the 20mm sorted out?

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## yulzari (May 1, 2018)

ChrisMcD said:


> Given the numbers of stockpiled Vickers,


As a digression. Does anyone know what was done with all these stockpiled Vickers? Lewis Guns turned up on ships and the Home Guard. Later Vickers Ks were employed in ground use and on small ships but I have never seen a photograph of any WW2 use of the Vickers bar in obsolete aeroplanes used for training or still in operational use (e.g Swordfish or Hart).


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## Juha2 (May 1, 2018)

yulzari said:


> As a digression. Does anyone know what was done with all these stockpiled Vickers? Lewis Guns turned up on ships and the Home Guard. Later Vickers Ks were employed in ground use and on small ships but I have never seen a photograph of any WW2 use of the Vickers bar in obsolete aeroplanes used for training or still in operational use (e.g Swordfish or Hart).



Lewises were used also to bolster the AA defences of the airfields, factories etc, IIRC at least some Vickers mgs were used for ground defences (against possible para or air landing troops attacks) of air fields.


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## Lefa (May 1, 2018)

Finns replaced the P36 engine cowling guns 12.7mm (one or two), wings 7.5mm are replaced by 7.7mm guns. (some planes, not all).
I do not know why not used the German 7.92, maybe was it impossible to place it on the wing? Or was 7.7 still more efficient?


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## Juha2 (May 1, 2018)

Lefa said:


> Finns replaced the P36 engine cowling guns 12.7mm (one or two), wings 7.5mm are replaced by 7.7mm guns. (some planes, not all).
> I do not know why not used the German 7.92, maybe was it impossible to place it on the wing? Or was 7.7 still more efficient?



7.7 mm Browning was a standard FiAF gun, so Finns used them, ammo and spare parts supply was in place, why to acquire one more 7.5 - 8 mm mg?


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## Smokey Stover (May 1, 2018)

Shortround6 said:


> Actually From the later MK Vs on they could have fitted 4 cannon if they wanted to, that was the whole idea of the "C" wing, it had the extra cannon bay built in and some MK V Spits on Malta got the 4 cannon., Insufficient gun heating and performance penalty stopped the fitting of 4 cannon until the 20 series.


I disagree, the canon heating, anti jamming problem was resolved way before the 20 series was produced. Infact the Hurricane and Spitfire had these freezing/gun jamming problems as early as the mk 1 browning .303 machine guns but was sorted out pretty quickly. So im not sure where this information is coming from.....
Plus the Hispano 20mm cannon were actually very reliable. From the Mk V onwards.


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## fastmongrel (May 1, 2018)

yulzari said:


> As a digression. Does anyone know what was done with all these stockpiled Vickers? Lewis Guns turned up on ships and the Home Guard. Later Vickers Ks were employed in ground use and on small ships but I have never seen a photograph of any WW2 use of the Vickers bar in obsolete aeroplanes used for training or still in operational use (e.g Swordfish or Hart).



They might have been stripped for parts for Army guns or even rebuilt into watercooled guns during the Invasion panic post Dunkirk.


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## Greyman (May 1, 2018)

Smokey Stover said:


> I disagree, the canon heating, anti jamming problem was resolved way before the 20 series was produced. Infact the Hurricane and Spitfire had these freezing/gun jamming problems as early as the mk 1 browning .303 machine guns but was sorted out pretty quickly. So im not sure where this information is coming from.....
> Plus the Hispano 20mm cannon were actually very reliable. From the Mk V onwards.



From everything I've read from the powers that be themselves it was due to the second issue (performance penalty).


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## Smokey Stover (May 1, 2018)

Greyman said:


> From everything I've read from the powers that be themselves it was due to the second issue (performance penalty).


I have not seen any material that suggests the Hispano cannons were any more prone to gun stoppages than any other fighter. A lot to do with it was poor or lack of proper maintenance on the ground, but again raf ground crew usually took great care and pride in their work knowing how important it was to give the pilot every chance of returning their aircraft. I have read accounts of Polish squadron mechanics in a frenzy when seeing their aircraft return to base. With one mechanic running along side his pilots Hurricane shouting "mine has been firing, mine has been firing!". As the red tape over the fighters gun ports would be missing if the machine had been using its guns. If by performance you mean weight/drop in speed, agility. Maybe in the very early days. One raf Hurricane early in 1940 was fitted with experimental twin 20mm cannon but it was so slow the aircraft could barely catch a bomber never mind anything else. But with the continuios uprating of the RR PV12 merlin these problems were soon offset.


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## Greyman (May 1, 2018)

yulzari said:


> As a digression. Does anyone know what was done with all these stockpiled Vickers?



I would guess they were able to be used up. Plenty of planes used them just before the war and a couple still were in the beginning. Supposedly the Swordfish kept its Mk.V until the very end of production ('44).

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## Greyman (May 1, 2018)

Smokey Stover said:


> I have not seen any material that suggests the Hispano cannons were any more prone to gun stoppages than any other fighter.



Sorry, when Shortround and I refer to performance penalty we mean the performance of the Spitfire, not the Hispano.


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## Smokey Stover (May 1, 2018)

Greyman said:


> Sorry, when Shortround and I refer to performance penalty we mean the performance of the Spitfire, not the Hispano.


Yes i edited my comment to cover that theory


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## Smokey Stover (May 1, 2018)

Greyman said:


> I would guess they were able to be used up. Plenty of planes used them just before the war and a couple still were in the beginning. Supposedly the Swordfish kept its Mk.V until the very end of production ('44).


Thats because the vickers machine gun was a tested and reliable weapon. It's the same reason the British kept the Browning .303. Again it was a very realiable weapon and could take British bullets not to mention easy to mass produce and already widespread. Later fighter bombers like the Beaufighter/Mossie and Typhoon kept x2/x4 .303s to help gauge trajectory for their main armament (rockets/cannon) when attacking ground or sea targets.


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## Greyman (May 1, 2018)

Smokey Stover said:


> If by performance you mean weight/drop in speed, agility. Maybe in the very early days.



When the AFDU compared the 'C' wing armaments (4x 20mm Spitfire vs. the 2x 20mm & 4x .303 Spitfire) they concluded the former was:

approximately 248 pounds heavier
was not as manoeuvrable at all heights, falling off rapidly above 20,000 feet
handling was 'exceedingly sloppy' above 30,000 feet
"at 28,000 feet ... it is thought that it could be easily out-manoeuvred by the Me.109F"
climb was not as good at all heights


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## pinsog (May 1, 2018)

Smokey Stover said:


> I disagree, the canon heating, anti jamming problem was resolved way before the 20 series was produced. Infact the Hurricane and Spitfire had these freezing/gun jamming problems as early as the mk 1 browning .303 machine guns but was sorted out pretty quickly. So im not sure where this information is coming from.....
> Plus the Hispano 20mm cannon were actually very reliable. From the Mk V onwards.



Apparently the 20mm cannon were a disaster over Darwin in 1943
http://www.darwinspitfires.com/index.php?page=the-spitfire-vc-s-faulty-armament


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## Smokey Stover (May 1, 2018)

Greyman said:


> When the AFDU compared the 'C' wing armaments (4x 20mm Spitfire vs. the 2x 20mm & 4x .303 Spitfire) they concluded the former was:
> 
> approximately 248 pounds heavier
> was not as manoeuvrable at all heights, falling off rapidly above 20,000 feet
> ...



Ok, with all due respect i think your leaning heavily on the evoluatiom of both aircraft. The Bf -109 was designed and manufactured almost two years ahead of the spitfire. So bearing that in mind, had both a/c started out at the same time the comparity would most certainly been different. By the time the Germans had enterered the 109F into combat one could argue the raf could have been rolling out the Spitfire mk IX. But lets stick with what we know as fact. What you are omitting to mention is when the 109F first went into combat in late 1940/early 1941, at lot of spitfires were still Mk ll's albeit with a more powerful engine. Early Bf - 109F's were initionally plagued with a few minor glitches. The 1,332hp DB601E engine was used in the 109F -3 & F-4 versions. And only 15 examples of the F-3 were known to be produced. Now after a few minor flight/tail problems were eliminated the F series did have a slight advantage in speed at altitude over the Spitfire. But the answer to that is dont get into a climbing fight with a 109-F. Secondly because of the dislike by some major German aces including Adolf Galland, the F series armament was problematic to say the least. Many pilots disliked the prop hub 15mm canon and two small calibre machine guns. So underwing 20mm gun pods were field adapted to many machines severely hampering performance. . An unexpected structural flaw of the wing and tail section was revealed when the first F-1s were rushed into service; some aircraft crashed or nearly crashed, with either the wing surface wrinkling or fracturing, or by the tail structure failing. In one such accident, the commander of JG 2 "Richthofen", Wilhelm Balthazar lost his life when he was attacked by a Spitfire during a test flight. While making an evasive manoeuvre, the wings broke away and Balthasar was killed when his aircraft hit the ground. Slightly thicker wing skins and reinforced spars dealt with the wing problems. Tests were also carried out to find out why the tails had failed, and it was found that at certain engine settings a high-frequency oscillation in the tailplane spar was overlapped by harmonic vibrations from the engine; the combined effect being enough to cause structural failure at the rear fuselage/fin attachment point. Initially, two external stiffening plates were screwed onto the outer fuselage on each side, and later the entire structure was reinforced. I admit until raf Mk V's knew how to dogfight favourably with the Bf -109F a lot of Spitfires were lost between late 40/early 41. But the situation was soon offset by the Mk IX that rained supreme for the rest of the war.

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## Smokey Stover (May 1, 2018)

pinsog said:


> Apparently the 20mm cannon were a disaster over Darwin in 1943
> http://www.darwinspitfires.com/index.php?page=the-spitfire-vc-s-faulty-armament


I think that was most likely down to the atrocious conditions. Sandstorms, severe weather, mud, and poor maintenance & lack of equipment, personal and hangers to protect or fix aircraft. Complex engine parts and sand/dust are not a good combination.


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## pinsog (May 1, 2018)

Smokey Stover said:


> I think that was most likely down to the atrocious conditions. Sandstorms, severe weather, mud, and poor maintenance & lack of equipment, personal and hangers to protect or fix aircraft. Complex engine parts and sand/dust are not a good combination.



The US 50’s worked. The Japanese 20mm and machineguns worked. The P39’s, P40’s, Wildcats (at Guadalcanal) and Zero’s all dealt with the same conditions and seemed to work.


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## Clayton Magnet (May 1, 2018)

Smokey Stover said:


> By the time the Germans had enterered the 109F into combat one could argue the raf could have been rolling out the Spitfire mk IX


Probably should have been fielding Spitfire mk.III's


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## tomo pauk (May 1, 2018)

Smokey Stover said:


> Ok, with all due respect i think your leaning heavily on the evoluatiom of both aircraft. The Bf -109 was designed and manufactured almost two years ahead of the spitfire. So bearing that in mind, had both a/c started out at the same time the comparity would most certainly been different. By the time the Germans had enterered the 109F into combat one could argue the raf could have been rolling out the Spitfire mk IX.
> ...
> I admit until raf Mk V's knew how to dogfight favourably with the Bf -109F a lot of Spitfires were lost between late 40/early 41. But the situation was soon offset by the Mk IX that rained supreme for the rest of the war.



Your evaluation of the good and bad points of the Bf 109F is a very good one, bar a detail or two. The Bf 109F1 and F2 were powered by engine with ~1000 HP at 20000 ft, and 1250 HP at 6000 ft, speed was around 375 mph at 20000 ft. But, more importantly for RAF, there was not a great number of the F1s and F2s around during the winter of 1940/41, and Eruopean winter was not conductive for air combat of the are anyway.
There was also a handful of 109F0 around, that were about equal to the Spitfire II.
However - RAF can't roll out the Spitfire Mk.IX before late 1941 since there is no two-stage Merlin around (and Spitfire IX didn't reigned supreme for the rest of the war, if we equal the reign with being best in every important category that makes a fighter).
'Some people' can argue all day long for the early introduction of the Spit IX, RAF's best bet for mid-1940 to early 1942 is Spitfire III with it's polished streamlining and resulting performance and range potential.

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## Smokey Stover (May 2, 2018)

tomo pauk said:


> Your evaluation of the good and bad points of the Bf 109F is a very good one, bar a detail or two. The Bf 109F1 and F2 were powered by engine with ~1000 HP at 20000 ft, and 1250 HP at 6000 ft, speed was around 375 mph at 20000 ft. But, more importantly for RAF, there was not a great number of the F1s and F2s around during the winter of 1940/41, and Eruopean winter was not conductive for air combat of the are anyway.
> There was also a handful of 109F0 around, that were about equal to the Spitfire II.
> However - RAF can't roll out the Spitfire Mk.IX before late 1941 since there is no two-stage Merlin around (and Spitfire IX didn't reigned supreme for the rest of the war, if we equal the reign with being best in every important category that makes a fighter).
> 'Some people' can argue all day long for the early introduction of the Spit IX, RAF's best bet for mid-1940 to early 1942 is Spitfire III with it's polished streamlining and resulting performance and range potential.



To be fair i have seen stats that show the polished/glitch free 109F could reach just over 400mph at 20,000 feet. But im always a little sceptical of numbers on paper as opposed to actual flight data. The two stage turbo Merlin was already on the design board by late 40 early 41, although i concede it was far from the polished part. Im actually not that big a fan of the Spitfire except the Mk l interceptor. I actually think the Hawker Tempest V (After the gremlins of the early Napier Sabre engine were eliminated) was a better fighter than the Spit Mk lX. And a lot of German airmen's accounts/war diaries agree that the Tempest was more of a concern than the Spit. Especially to Fw 190 pilots who found out much to their cost they could not escape the Tempest in a dive or straight line speed. Even Me 262 pilots feared the Tempest more than any other allied fighter. And i have not come across any issues with the x4 20mm hispano short barrelled canon either by stoppages or speed/flight control handicaps But then the Sabre engine was quite a beast capable of huge power bursts albeit at the pilots risk of overheating/internal damage if used in excess. The Bf 109F was probably where Messerschmitt should have drawn the line on the 109 series. It's almost universally agreed by luwftwaffe pilots that the Freidrich was the most agile and fastest Mk of all types and yet fewer F models were built than any other Mk. As Galland once said, they should have concentrated on refining the F series while upscaling the Fw 190 production. At least until the Me 262 could be rolled out in numbers with better technology.


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## fastmongrel (May 2, 2018)

Smokey Stover said:


> The two stage turbo Merlin was already on the design board



Probably a typo but their never was a Turbocharged Merlin

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## Smokey Stover (May 2, 2018)

fastmongrel said:


> Probably a typo but their never was a Turbocharged Merlin


Ok, so supercharger then. A turbo is powered by exhaust gasses and therefore has lag, while a supercharger is usually chain or belt driven providing constant power without the drop off in performance. So maybe it's not quite splitting hairs but its close...


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## Smokey Stover (May 2, 2018)

Ok, so maybe this will clear things up about the 20mm British Hispano Suiza.
In the buildup to the Second World War, the United Kingdom had embarked on a programme to develop cannon-armed fighters.[4] They acquired a licence to build the HS.404, which entered production as the *Hispano Mk.I* intended as aeroplane armament. Its first use was in the Westland Whirlwind of 1940, and later in the more powerful Bristol Beaufighter, providing the Royal Air Force with powerful cannon-armed interceptors.[5] The experience of the Battle of Britain had shown the batteries of eight rifle-calibre machine guns to be inadequate and prompted the adoption of auto cannon armament for the primary portion of Royal Air Force (RAF) fighters.[6] The Beaufighter highlighted the need for a belt feed mechanism; as a night fighter the 60-round drums needed to be replaced in the dark by the Radar/Wireless Operator, often while the aircraft was manoeuvering to keep sight of its quarry. In addition, the early trial installations in the Hawker Hurricane and Supermarine Spitfirehad shown a tendency for the gun to jam during combat manoeuvres, leading to some official doubt as to the suitability of cannon as the sole main armament. This led to the Air Ministry for a brief period specifying 12-machine gun armament for new fighters.[6]

Subsequently, a suitable belt-feeding system was developed by Martin-Baker, and the new design was adopted by the RAF and Fleet Air Arm in 1941 in a slightly modified form as the *Hispano Mk.II*. Four cannon replaced the eight .303 Browning machine guns in the Hurricane[7] and in some tropical versions of the Spitfire, becoming standard armament in later fighters. Most other Spitfires had only two cannon, because outboard cannon tended to freeze at high altitudes, along with four 0.303 calibre (7.7mm) or two 0.50 calibre (12.7mm) machine guns.[8]

The British were concerned their production would be inadequate and licensed production of the Hispano to the US. However, the US production never became satisfactory and the British eventually gave up on the U.S. versions. British production was eventually increased to the point where this was no longer an issue. The ultimate version of the British wartime Hispanos was the *Hispano Mk. V*, which had a shorter barrel, and lacked the cocking cylinder thus requiring manual cocking before flight. It was lighter and had a higher rate of fire (desirable in aircraft armament), although at the expense of some muzzle velocity. The shorter barrel meant that the weapon could be housed within the wing of a fighter plane, reducing drag and making them less vulnerable to freezing and mechanical stress. One of the main British fighters to use the *Mk. V* was the Hawker Tempest Mk. V Series II, which mounted two cannon in each wing.[9] Ammunition types available included Semi-Armour Piercing, Incendiary (SAPI) and High Explosive, Incendiary (HEI).[10] Around 42,500 Hispano cannon of various Marks were manufactured by Birmingham Small Arms (BSA).
In the buildup to the Second World War, the United Kingdom had embarked on a programme to develop cannon-armed fighters.[4] They acquired a licence to build the HS.404, which entered production as the *Hispano Mk.I* intended as aeroplane armament. Its first use was in the Westland Whirlwind of 1940, and later in the more powerful Bristol Beaufighter, providing the Royal Air Force with powerful cannon-armed interceptors.[5] The experience of the Battle of Britain had shown the batteries of eight rifle-calibre machine guns to be inadequate and prompted the adoption of auto cannon armament for the primary portion of Royal Air Force (RAF) fighters.[6] The Beaufighter highlighted the need for a belt feed mechanism; as a night fighter the 60-round drums needed to be replaced in the dark by the Radar/Wireless Operator, often while the aircraft was manoeuvering to keep sight of its quarry. In addition, the early trial installations in the Hawker Hurricane and Supermarine Spitfirehad shown a tendency for the gun to jam during combat manoeuvres, leading to some official doubt as to the suitability of cannon as the sole main armament. This led to the Air Ministry for a brief period specifying 12-machine gun armament for new fighters.[6]

Subsequently, a suitable belt-feeding system was developed by Martin-Baker, and the new design was adopted by the RAF and Fleet Air Arm in 1941 in a slightly modified form as the *Hispano Mk.II*. Four cannon replaced the eight .303 Browning machine guns in the Hurricane[7] and in some tropical versions of the Spitfire, becoming standard armament in later fighters. Most other Spitfires had only two cannon, because outboard cannon tended to freeze at high altitudes, along with four 0.303 calibre (7.7mm) or two 0.50 calibre (12.7mm) machine guns.[8]
In the buildup to the Second World War, the United Kingdom had embarked on a programme to develop cannon-armed fighters.[4] They acquired a licence to build the HS.404, which entered production as the *Hispano Mk.I* intended as aeroplane armament. Its first use was in the Westland Whirlwind of 1940, and later in the more powerful Bristol Beaufighter, providing the Royal Air Force with powerful cannon-armed interceptors.[5] The experience of the Battle of Britain had shown the batteries of eight rifle-calibre machine guns to be inadequate and prompted the adoption of auto cannon armament for the primary portion of Royal Air Force (RAF) fighters.[6] The Beaufighter highlighted the need for a belt feed mechanism; as a night fighter the 60-round drums needed to be replaced in the dark by the Radar/Wireless Operator, often while the aircraft was manoeuvering to keep sight of its quarry. In addition, the early trial installations in the Hawker Hurricane and Supermarine Spitfirehad shown a tendency for the gun to jam during combat manoeuvres, leading to some official doubt as to the suitability of cannon as the sole main armament. This led to the Air Ministry for a brief period specifying 12-machine gun armament for new fighters.[6]


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## Shortround6 (May 2, 2018)

I would hope the Tempest was a better fighter than the MK IX Spitfire.

It took until Sept of 1944 to get five operational squadrons of Tempests into service. Just over two years earlier (Aug 1942) there were 4 squadrons of MK IX Spitfires. 
First Tempest squadron/s went operational in April of 1944. First Spitfire two stage Griffon squadron (No 610) went operational in Dec 1943. Six squadrons in the 2nd TAF by Dec 1944. 

The Tempest is going to look fantastic compared to a plane that was 2 years older, compared to an old airplane with an up to date engine the difference is not anywhere near as marked.

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## Smokey Stover (May 3, 2018)

Shortround6 said:


> I would hope the Tempest was a better fighter than the MK IX Spitfire.
> 
> It took until Sept of 1944 to get five operational squadrons of Tempests into service. Just over two years earlier (Aug 1942) there were 4 squadrons of MK IX Spitfires.
> First Tempest squadron/s went operational in April of 1944. First Spitfire two stage Griffon squadron (No 610) went operational in Dec 1943. Six squadrons in the 2nd TAF by Dec 1944.
> ...



Initially i agree, the Spitfire was after all a 1930's design. But engine wise, the evolution of the Spit from a small black merlin to a huge Griffon powered machine with X4 20mm canon in later/last models such as the Mk 22 clearly showed just how versatile and easy the basic design was to constantly update deserves much credit. And even though the Tempest ll was effectively a post war fighter, (Mainly due to the scarcity of the Bristol Centaurus radial engine) was in most respects a better aircraft than the Tempest V. It had a better roll rate, more powerful and reliable engine and spawned a new fast modern post war aircraft carrier fighter. The Hawker Sea Fury. I guess sometimes regardless of which aircraft is best some planes just hold more of a soft spot in our heart. For example the Spitfire was and is one of the most graceful, practical fighters of its day. But i still prefer the Hawker Hurricane.....


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## tomo pauk (May 3, 2018)

Smokey Stover said:


> To be fair i have seen stats that show the polished/glitch free 109F could reach just over 400mph at 20,000 feet. But im always a little sceptical of numbers on paper as opposed to actual flight data. The two stage turbo Merlin was already on the design board by late 40 early 41, although i concede it was far from the polished part.
> ....



The Bf 109F4 should be able to beat 400 mph mark once the DB 601E s cleared for 'Notleistung', that being winter of 1941/42 (it was ~390 mph before that). As fast commented above - no turbo on Spitfires. Engines that are already on the design board will not power any aircraft, this is what produced and installed engines do.



> ....
> And i have not come across any issues with the x4 20mm hispano short barrelled canon either by stoppages or speed/flight control handicaps But then the Sabre engine was quite a beast capable of huge power bursts albeit at the pilots risk of overheating/internal damage if used in excess. The Bf 109F was probably where Messerschmitt should have drawn the line on the 109 series. It's almost universally agreed by luwftwaffe pilots that the Freidrich was the most agile and fastest Mk of all types and yet fewer F models were built than any other Mk. As Galland once said, they should have concentrated on refining the F series while upscaling the Fw 190 production. At least until the Me 262 could be rolled out in numbers with better technology.



Short-barreled Hispano, the Mk.II, entered service some 4 years after the British-made Hispano II, on Tempest. One might expect that engineers and technicians figured out a thing or two about cann'ns' installations. We can also recall that both Hurricane and Typhoon were featuring unproblematic cannon installations.
German pilot or two is indeed entitled to it's opinion, yet the Bf 109Fs were not the fastest 109s. Agility was a part of light armament and fuel load, some other German pilots compained about lack of firepower (so many of the 109s got gondola cannons), and we know that 109 was unable to provide real long-range work in Zero or P-51 league - confirming the 'no free lunch' rule once again. The Bf 109G2 was a refined 109F4, production of the Fw 190 was being upscaled as possible anyway.



Smokey Stover said:


> Ok, so maybe this will clear things up about the 20mm British Hispano Suiza.
> <snip>



Interesting. Your work?


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## Smokey Stover (May 4, 2018)

The Allied aircraft designers believed that the 50 (.5) caliber and the 20mm were satisfactory weapons. They were capable of taking down aircraft, fighters, heavy bombers as well as dealing with a lot of ground installations.
The Allied forces preferred weapon systems that were jack of all trades; and they preference standardization over optimization. The Germans on the other hand preferred weapons that were highly specialized. They developed heavier guns to deal with enemy tanks. They even tried it out on enemy bombers with mixed results. But those same heavily armed aircraft were slow, and vulnerable to enemy fighters. Almost every model and manufacturer from Browning, to Hispano to Oerlikon all had problems either reliability or rate of fire/load capacity. It all depended on what a fighters armament was designed to be used against. Ie: Other fighters, bombers, tanks, shipping or ground targets. I remember reading one B-25 Mitchell pilot’s account of the 75mm gun performance and they hated it. There was one time they actually managed to hit a small ship with it and it spectacularly exploded. But they decided not to report that the 75mm scored the kill in case the higher brass decided to give them more heavily armed aircraft. The same was said about the Mosquito's 57mm molins gun. A 6 round capacity is hardly efficient for any aircraft. And one of the reasons the British didnt go above 20mm weapons in fighters was simply down to weight/flight characteristics being rapidly reduced. Some aircraft like the US 37mm airacobra and the Russian 23mm and 37mm guns werre for specific targets, and not so much other fighters.
We all agree the purpose of the gun is to damage the target, right? So when your considering the answer to such a question, you have to consider what the weapon is firing at, regardless of what the weapon is carried on. For the majority of the war, Allied fighters with MGs were rarely shooting at bombers, ships or other armored targets. They were aiming at the other sides’ fighters. These rarely required big shells to damage. And the goal was to cause damage, rendering the target unable to perform its mission, not necessarily to blow it up every time. Same reasoning applies to naval guns. Destroyers were never intended to fight battleships so no 16″ main guns. There’s also other factors such as the number of rounds carried, fewer if bigger, and the speed of the target, requiring more shots to hit it. Most of the cannons of the day fired so slowly that is was very hard to hit high speed targets. Notice how the later in the war, the bigger the guns became. The Axis nations were more concerned with shooting down bombers, which of course are bigger, slower and harder to bring down. I think the Brits went from their .303 to cannons because they never seemed to have that big machine gun round.
If you consider planes designed to attack ground targets or ships, the cannon get bigger or you see a switch to rockets, which can carry a much bigger payload, usually explosive. Their targets were not moving, slow moving and/or resistant to bullets. But a plane might only carry 8 rockets due to space and weight. And lack of guidance. The Russian guns you mention were primarily meant to shoot German armor as I recall. The .50 cal. Browning was probably close to perfect for attacking other planes or lightly armored targets. Groups of these bad boys were mounted on twin engine bombers in the Pacific and were able to blow holes through the sides of Japanese destroyers. It was still used in US interceptors into Korea. Same effects when mounted on vehicles. The .30 cal was the infantry support weapon because it was meant to shoot men. A .50 was overkill. And heavy.

To sum up: A successful weapon design is rarely a case of building it you because you can but building it to damage a certain type of target well. If it can be used in multiple roles, even better.


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## fastmongrel (May 4, 2018)

Smokey Stover said:


> The same was said about the Mosquito's 57mm molins gun. A 6 round capacity is hardly efficient for any aircraft.



The Mosquito Tsetse carried 25 rounds of 6 pounder 57mm though I have seen claims it carried 28 rounds, possibly the magazine was 25 but 3 more could be loaded 1 in the breech 2 in the loading mechanism.



Smokey Stover said:


> Groups of these bad boys were mounted on twin engine bombers in the Pacific and were able to blow holes through the sides of Japanese destroyers



The shell plating on a Destroyer was thin Mild Steel you could poke a hole in it and maybe kill or wound some crew but the Destroyer will still be sailing and fighting. As .50 rounds would break up when hitting water there would be no holes below the waterline so all you are really doing is improving the ventilation a tiny bit. 

RAF Coastal Command Beaufighters and Mosquitos had a heavier armament than the .50 equipped US attack bombers but they never managed to sink anything bigger than a wooden Trawler with gunfire alone.

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## fastmongrel (May 4, 2018)

A story about the M2 .50 as told to me by a friend who served in Iraq. Car drives through the stop point at a camp obviously a suicide bomber. A US Humvee opened up at about 700 yards with its M2 brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmm car dodges left and right and carries on brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm car is now about 350 yards away still dodging everyone watching is now looking for places to hide behind brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
car dodges left and right but hits the concrete blocks about 100 yards from the gate and rolls into a ditch with the engine revving madly. bbbbrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm....BOOM car explodes M2 gunner whoops punches the air and gets a medal. My friend decides to keep well away from the camp walls and sends in a transfer request to somewhere with fewer suicide car bombs.

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## pinsog (May 4, 2018)

fastmongrel said:


> A story about the M2 .50 as told to me by a friend who served in Iraq. Car drives through the stop point at a camp obviously a suicide bomber. A US Humvee opened up at about 700 yards with its M2 brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmm car dodges left and right and carries on brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm car is now about 350 yards away still dodging everyone watching is now looking for places to hide behind brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
> car dodges left and right but hits the concrete blocks about 100 yards from the gate and rolls into a ditch with the engine revving madly. bbbbrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm....BOOM car explodes M2 gunner whoops punches the air and gets a medal. My friend decides to keep well away from the camp walls and sends in a transfer request to somewhere with fewer suicide car bombs.



50 caliber or 20mm, you still have to hit the target to kill it. (My apologies if this was just a war story and not a ‘50 BMG is ineffective on Toyota’s’ story)


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## Smokey Stover (May 4, 2018)

fastmongrel said:


> The Mosquito Tsetse carried 25 rounds of 6 pounder 57mm though I have seen claims it carried 28 rounds, possibly the magazine was 25 but 3 more could be loaded 1 in the breech 2 in the loading mechanism.
> 
> 
> 
> ...


Sorry i was referring to the Mossie/B-25 fire rate, which while a/c like the B-25 could carry up to 21 shells. An attack run left the aircraft very vulnerable as only 4-5 shells could be fired off at one time. Then it was the unfortunate job of the navigator to manhandle more into the breach/gunbay. These kinds of large calibre bombers were simply not effective and pilots did not like flying them. Im not 100% about the Mossie, but there is no way 21 75mm rounds that could be fired none stop, and even if there was the barrel would be toast/bent to hell and back


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## Smokey Stover (May 4, 2018)

fastmongrel said:


> A story about the M2 .50 as told to me by a friend who served in Iraq. Car drives through the stop point at a camp obviously a suicide bomber. A US Humvee opened up at about 700 yards with its M2 brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmm car dodges left and right and carries on brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm car is now about 350 yards away still dodging everyone watching is now looking for places to hide behind brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
> car dodges left and right but hits the concrete blocks about 100 yards from the gate and rolls into a ditch with the engine revving madly. bbbbrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm....BOOM car explodes M2 gunner whoops punches the air and gets a medal. My friend decides to keep well away from the camp walls and sends in a transfer request to somewhere with fewer suicide car bombs.


I dont mean to make light of the situation but at 350 yards one wonders where that guy learnt to shoot.....


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## Greyman (May 4, 2018)

fastmongrel said:


> The Mosquito Tsetse carried 25 rounds of 6 pounder 57mm though I have seen claims it carried 28 rounds, possibly the magazine was 25 but 3 more could be loaded 1 in the breech 2 in the loading mechanism.



A&AEE trials/examination of the installation say 23-round magazine and one in the chamber (24 total).

EDIT: Weights & Loading / CG data also indicate 24 rounds total.


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## pbehn (May 4, 2018)

I would think with the rate of fire of the gun and the speed of a mosquito it rarely used all the shells it carried.

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## Clayton Magnet (May 4, 2018)

Smokey Stover said:


> I think the Brits went from their .303 to cannons because they never seemed to have that big machine gun round.


They had piles of the Vickers .50 sitting around, and the Browning M2 was still unreliable on a wing mount. They skipped the .50 because cannons proved to be superior.


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## Glider (May 4, 2018)

The Germans had a great respect for the 6pd in the Mosquito. It was very accurate and often used to attack the bridge or AA guns from a distance. The RAF were also keen on them but the rocket was very capable of sinking a small ship which the 6pd wasn't so the emphasis was switched to the rockets and the use of the 6pd wasn't extended

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## Shortround6 (May 4, 2018)

Clayton Magnet said:


> They had piles of the Vickers .50 sitting around, and the Browning M2 was still unreliable on a wing mount. They skipped the .50 because cannons proved to be superior.




The .5 Vickers was used as an AA gun or light tank/armoured car gun. I don't believe it was ever used in a production aircraft. The .303 Vickers as NEVER used where the pilot (or crewman) could not get to it in case of a jam. I doubt the .5in Version was any different. That is one big reason for going to the .303 Browning. They wanted a gun that could be mounted in remote areas of the aircraft. 

Please look at earlier posts, the .50cal ammo of the 1920s and early/mid 30s (and even British contract ammo of 1940) was loaded to about the same velocity as the .5 Vickers except it used a heavier bullet so the difference in hitting power was much less. The Later ammo was over 20% more powerful. This lower powered ammo makes the british decision to skip the .50 Browning at the time (Pre BOB much easier to understand.


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## Greyman (May 4, 2018)

Shortround6 said:


> The .303 Vickers as NEVER used where the pilot (or crewman) could not get to it in case of a jam.



This doesn't appear to be true, looking at the early Blenheim, Battle and Gladiator.


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## Shortround6 (May 4, 2018)

Greyman said:


> This doesn't appear to be true, looking at the early Blenheim, Battle and Gladiator.



I know it is Wiki but....................
"During flight tests, the prototype attained a top speed of 242 mph (389 km/h; 210 kn) while carrying the required four .303 in (7.7 mm) machine guns (two synchronised Vickers guns in the fuselage and two Lewis guns under the lower wing).[5] "

" All MK II Gladiators also carried Browning 0.303-inch machine guns (licence-manufactured by the BSA company in Birmingham) in place of the Vickers-Lewis combination of the MK I."

The First quote is attributed to Francis Mason and not surprisingly his book on British fighters says pretty much the same thing. Early Blenheim and Battle's may have had a Vickers but they switched to Brownings fairly soon. How many planes were retro fitted I have no idea.


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## Greyman (May 4, 2018)

The Lewis-winged version was an even older variation. The four-Vickers version was an intermediary between that and the four-Browning version. Though it seems to be mostly done to prepare the plane for the new Browning installation rather than a real need to replace the wing-mounted Lewis (the belt-fed Vickers installation being very similar to the upcoming Browning).


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## fastmongrel (May 4, 2018)

pinsog said:


> 50 caliber or 20mm, you still have to hit the target to kill it. (My apologies if this was just a war story and not a ‘50 BMG is ineffective on Toyota’s’ story)



The punchline to the story, the GIs on the gate had guided Anti Tank Missiles the next day.


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## pinsog (May 4, 2018)

fastmongrel said:


> The punchline to the story, the GIs on the gate had guided Anti Tank Missiles the next day.



That’s funny! Although my personal choice if forced into that setting would be a 7.62 minigun. 6,000 rounds per minute would handle anything not armored. Instant action, point and shoot. I wouldn’t think you would have time to deploy a guided missile in that short amount of time


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## swampyankee (May 5, 2018)

Smokey Still łmover said:


> Sorry i was referring to the Mossie/B-25 fire rate, which while a/c like the B-25 could carry up to 21 shells. An attack run left the aircraft very vulnerable as only 4-5 shells could be fired off at one time. Then it was the unfortunate job of the navigator to manhandle more into the breach/gunbay. These kinds of large calibre bombers were simply not effective and pilots did not like flying them. Im not 100% about the Mossie, but there is no way 21 75mm rounds that could be fired none stop, and even if there was the barrel would be toast/bent to hell and back





Glider said:


> The Germans had a great respect for the 6pd in the Mosquito. It was very accurate and often used to attack the bridge or AA guns from a distance. The RAF were also keen on them but the rocket was very capable of sinking a small ship which the 6pd wasn't so the emphasis was switched to the rockets and the use of the 6pd wasn't extended




Of course, the other shoe is that a big gun, like the 6-pdr on the Mosquito or the 75 mm on the B-25 is always there, but rockets aren't.

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## Glider (May 5, 2018)

swampyankee said:


> Of course, the other shoe is that a big gun, like the 6-pdr on the Mosquito or the 75 mm on the B-25 is always there, but rockets aren't.


True, but the idea was to stop the target from being there and to do that, the RAF found the rocket to be more effective against shipping. Now had the RAF faced large formations of B17 type bombers, then the 6pd would have really been an interesting option


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## Ascent (May 5, 2018)

The advantage of rockets is that all the Mosquitoes could carry them rather than having a limited number of MK XVIII's with the 57mm. Once rockets were introduced no more MK XVIII's were produced. Also with rockets you still had four 20mm cannon which could be used for flak suppression.

Overall a Mosquito with 8 rockets and 4 20mm was a more flexible option than one with a 57mm.

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## Smokey Stover (May 6, 2018)

Glider said:


> True, but the idea was to stop the target from being there and to do that, the RAF found the rocket to be more effective against shipping. Now had the RAF faced large formations of B17 type bombers, then the 6pd would have really been an interesting option


Im not so sure about rockets being effective against aircraft/bomber formations. Didnt the Luftwaffe try that on US day bomber sorties? From what i've read it wasn't all that successful or even practical. A bit haphazard with mixed results. Not to mention aircraft loaded up with rockets and heavy canon were meat on the table for escorting fighters.


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## pbehn (May 6, 2018)

Smokey Stover said:


> Im not so sure about rockets being effective against aircraft/bomber formations. Didnt the Luftwaffe try that on US day bomber sorties? From what i've read it wasn't all that successful or even practical. A bit haphazard with mixed results. Not to mention aircraft loaded up with rockets and heavy canon were meat on the table for escorting fighters.


The 6 pounder is a gun, the RP-3 (3inch diameter) rocket is sometimes called a 60ib rocket (explosive) or 25ib rocket (armour piercing).


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## Glider (May 6, 2018)

I was trying to say that the Mosquito with the 6pd would have been an interesting option. It was accurate, had a good rate of fire (for a gun of its type), almost certainly a one hit kill depending on how lucky the target crew were and it had a limited impact on the Mosquito's performance.

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## Ascent (May 6, 2018)

I believe one MK XVIII got a kill with the 57mm. Can't remember what it was, think probably a single engine fighter but very much a lucky shot.

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## Smokey Stover (May 6, 2018)

Exactly. 6 pdr or rocket, the odds of even getting the gunsight on a fast moving airborne target would be hard enough for a ww2 a/c nevermind actually hitting the thing. I would have thought bomber gunners poor to non existent kill rates was proof enough of that, and they were only using .50's.


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## Glider (May 6, 2018)

Smokey Stover said:


> Exactly. 6 pdr or rocket, the odds of even getting the gunsight on a fast moving airborne target would be hard enough for a ww2 a/c nevermind actually hitting the thing. I would have thought bomber gunners poor to non existent kill rates was proof enough of that, and they were only using .50's.


I'm sorry but I don't think you understand what I am trying to say. The 6pd in the Mosquito was very accurate capable of hitting a coasters bridge or main AA guns at a closing speed of approx. 300mph. Obviously they would be pretty useless against a small fast fighter, but against a large B17 type bomber they stood a good chance of a hit and downing the bomber with one hit.
A B17 is a lot bigger than an AA gun and a coasters bridge, the closing speed would be around 100 mph and this would all be to the advantage of the attacking aircraft.


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## yulzari (May 8, 2018)

For an HE round the 6 pounder could have been built around the 75mm case/shell as was done for tanks. Not a rebore, as sometimes stated, but a new barrel and the chamber made for the French/US case. So now you are firing a 3 inch semi automatic gun at a destroyer. Despite claims of a ROF at 3s seconds per round period film demonstrates other claims of just under one round per second are more representative. Now add a proximity fuse and you get a plausible bomber downing capability. The down side is that you have a large twin engined aeroplane with a heavy load (gun/loader) at the mercy of escorting single engined fighter and a larger target for the bombers defence guns.

The 75mm swapped velocity of flight for weight of shell with the end result being little difference in the forces involved at the firing end. As said above, what the 3" rocket projectile brought was flexibility, even if the accuracy was appalling.

BTW just to mention. The B25 75mm gun was hand loaded which is hard enough on the ground never mind in a small space moving in 3 dimensions with huge gravity issues. Worse than a tank. Reloading 20mm cannon drums in a night fighter Beaufighter was bad enough.

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## fastmongrel (May 8, 2018)

yulzari said:


> Now add a proximity fuse



Good idea but not happening in WWII unfortunately. The smallest workable Proximity fuses in WWII were for the 3.7"/90mm AA guns anything smaller and there was no room for a decent HE payload. It was the 50s before Proximity fuses got small enough for a 3 inch.


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## Glider (May 8, 2018)

I know its getting to the realms of fantasy but anyone thought of putting a proximity fuse on the rockets?


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## fastmongrel (May 8, 2018)

Glider said:


> I know its getting to the realms of fantasy but anyone thought of putting a proximity fuse on the rockets?



The 3 inch Z battery AA rockets had an early Photo-Electric proximity fuse but it didnt work too well apparently. It worked okay on a sunny day when fired away from the Sun but it didnt work when fired on a cloudy day or towards the sun.

3" Z Battery


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## Greyman (May 8, 2018)

yulzari said:


> Despite claims of a ROF at 3s seconds per round period film demonstrates other claims of just under one round per second are more representative.



I'm always wary of using films for that sort of thing, as you don't know the speed/frame rate at which the footage was captured or played back (or copied/recopied in the intervening decades).

British tests say the 6pdr ROF on automatic 'is slightly more than one round per second' - but that it was worse in every way compared to semi-automatic fire.

An aimed shot could be fired at 1.1 to 1.5 second intervals on semi-automatic. Accuracy was most impressive - in good weather reasonable results could be expected against a medium tank-sized target from ranges up to 1200 to 1300 yards(!).


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## Smokey Stover (May 8, 2018)

yulzari said:


> For an HE round the 6 pounder could have been built around the 75mm case/shell as was done for tanks. Not a rebore, as sometimes stated, but a new barrel and the chamber made for the French/US case. So now you are firing a 3 inch semi automatic gun at a destroyer. Despite claims of a ROF at 3s seconds per round period film demonstrates other claims of just under one round per second are more representative. Now add a proximity fuse and you get a plausible bomber downing capability. The down side is that you have a large twin engined aeroplane with a heavy load (gun/loader) at the mercy of escorting single engined fighter and a larger target for the bombers defence guns.
> 
> The 75mm swapped velocity of flight for weight of shell with the end result being little difference in the forces involved at the firing end. As said above, what the 3" rocket projectile brought was flexibility, even if the accuracy was appalling.
> 
> BTW just to mention. The B25 75mm gun was hand loaded which is hard enough on the ground never mind in a small space moving in 3 dimensions with huge gravity issues. Worse than a tank. Reloading 20mm cannon drums in a night fighter Beaufighter was bad enough.


Well said.


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## Smokey Stover (May 8, 2018)

Greyman said:


> I'm always wary of using films for that sort of thing, as you don't know the speed/frame rate at which the footage was captured or played back (or copied/recopied in the intervening decades).
> 
> British tests say the 6pdr ROF on automatic 'is slightly more than one round per second' - but that it was worse in every way compared to semi-automatic fire.
> 
> An aimed shot could be fired at 1.1 to 1.5 second intervals on semi-automatic. Accuracy was most impressive - in good weather reasonable results could be expected against a medium tank-sized target from ranges up to 1200 to 1300 yards(!).


Then why have i heard claims from ex ww2 mossie pilots that the six pounder version, even with small calibre bullets to use as a means of sighting/gauging accuracy, were absolutely rubbish. The recoil alone (The six pounder kicked like a mule) often sent the shell off to the left or right of target and to make more than one firing pass was basically suicide. So they had one go and maybe 4-6 rounds to get it right and hit their targets. A lot of mossie pilots preferred the cannon/machine gun + underwing rocket version. And thought the molins cannon to be too much. Not to mention firing the gun repeatedly often caused structural damage that although minor to begin with could prove fatal if missed by ground crew and left to deteriorate.


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## Greyman (May 8, 2018)

Smokey Stover said:


> Then why have i heard claims ...



I'd have to have a look at those accounts myself to comment. At Boscome Down all pilots found the setup quite suitable.

Using the .303s to aim instead of a carefully harmonised gunsight seems incorrect.


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## Greyman (May 9, 2018)

Some final assessments from the A&AEE:

The aircraft is eminently suitable for low attack work and is an ideal gun platform for the Tsetse installation. The chief features which lead to this conclusion are as follows:-

The good stability and manoeuvrability of the aircraft.
The speed with which attacks can be made stimulates confidence in the pilot.
The aircraft attitude during low attack is such that the pilot does not have to worry about his position relative to the ground.
The throw-off at the time of firing is so slight that maintenance of aim is simple.
The extremely good forward view from the aircraft gives the maximum opportunity for small targets to be picked up and held in the sight.
The rudder control is sufficiently sensitive to enable quick lateral sighting corrections. When the rudder controls are used as intended there is no tendency to overcorrection.

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## fastmongrel (May 9, 2018)

Smokey Stover said:


> Then why have i heard claims from ex ww2 mossie pilots that the six pounder version, even with small calibre bullets to use as a means of sighting/gauging accuracy, were absolutely rubbish.



Personal recollections have proved many times over to be faulty. I remember on another forum a WWII veteran who repeatedly swore blind that his regiments Churchill tanks had Meadows flat12 engines even though all records show that they were never fitted and indeed could not have been fitted as they would not have matched up to the transmission. He had almost certainly got his Churchill tank mixed up with the Covenanter tank which was fitted with the Meadows flat12 and was the main training tank used in Britain 1941 to 44.

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## Glider (May 9, 2018)

Smokey Stover said:


> Then why have i heard claims from ex ww2 mossie pilots that the six pounder version, even with small calibre bullets to use as a means of sighting/gauging accuracy, were absolutely rubbish. The recoil alone (The six pounder kicked like a mule) often sent the shell off to the left or right of target and to make more than one firing pass was basically suicide. So they had one go and maybe 4-6 rounds to get it right and hit their targets. A lot of mossie pilots preferred the cannon/machine gun + underwing rocket version. And thought the molins cannon to be too much. Not to mention firing the gun repeatedly often caused structural damage that although minor to begin with could prove fatal if missed by ground crew and left to deteriorate.


All I can add to this posting are the comments from the father of my son's girlfriend. He served in the German navy on the flak boats off Norway and they hated the accuracy of the big gun Mosquito as he called them. If you were on a flak island or the bridge you just hoped that the pilot wanted to shoot at the other target. It seemed personal, that they were aiming at you not just the ship.

This might be of interest. It also covers the shooting down of a Ju88 with the 57mm

_View: https://www.youtube.com/watch?v=pX-IxiZyGRk_


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## Walrus (May 17, 2018)

fastmongrel said:


> Do some research before posting and you will find that most RAF pilots in Aug/Sept 1940 had very poor shooting skills.



My bad
RAF pilots were incompetent and couldn't hit a flying barn door at 5 yards. 
The Battle of Britain was a resounding victory for the superior numbers of the Luftwaffe.
Operation Sea Lion was able to go ahead and I'm writing this in German. 

All Hail the Thousand Year Reich


There are many factors to consider before you roundly criticise ALL RAF pilots of being unable to shoot
You need to do some serious rethinking

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## tomo pauk (May 17, 2018)

This is getting hillaroius quickly.


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## fastmongrel (May 18, 2018)

Walrus said:


> My bad
> RAF pilots were incompetent and couldn't hit a flying barn door at 5 yards.
> The Battle of Britain was a resounding victory for the superior numbers of the Luftwaffe.
> Operation Sea Lion was able to go ahead and I'm writing this in German.
> ...



I am going to assume you dont have English as a first language and Google translate has let you down so I am posting my original post on this topic over which you have got your whiskers all twisted. I have highlighted the relevant section.

_Theres also the fact that _*many*_ RAF pilots in 1940 could have been flying aircraft armed with Laser equipped Sharks and they still wouldnt have shot anything down.
_
Many RAF pilots in 1940 couldnt hit the proverbial Barn door even if they had been holding the Barn door handle. Its not insulting or derogatory its an easily provable fact.

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## MycroftHolmes (May 19, 2018)

fastmongrel said:


> Many RAF pilots in 1940 couldnt hit the proverbial Barn door even if they had been holding the Barn door handle. Its not insulting or derogatory its an easily provable fact.



Proof for this absurd statement? There's no evidence that German and American pilots were any better marksmen than British. RAF standards were simply higher than in other air-forces, so it's a case of RAF pilot gets 10% hits and the RAF are like "That's not good enough"; Luftwaffe or USAAF/USN pilot gets 10% hits and it's "That's fine, no need to worry".


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## Shortround6 (May 19, 2018)

Hits were more like 2% for average pilots.

There is evidence of studies done by ground observers and gun camera film of British pilots in training opening fire on towed target sleeves at distances 3 to 4 times the range they were instructed to open fire at. 900-1200 yds instead of 300yds. Obviously any hits at those ranges were total accidents. The British had not spent a lot of time/effort on air to air gunnery training before the war and indeed there were several schemes and an awful of money spent on ways to get around training pilots in air to air shooting. The schemes for zero aim off shooting and the turret fighter craze. Also the 1939/early 40 spread patterns for the wing guns. Higher ups simply thought that you couldn't train pilots to deal with the closing speeds and brief firing opportunities of high speed flight. 
Some pilots and squadron commanders may have thought this was rubbish and done what they could to plan around it but with that attitude being the official stance for the end of the 30s actual gunnery (air to air) firing was a tiny fraction of the pilots training.
Other air forces may have had different priorities and it depends on which squadrons and commanders you are talking about. 
For the USN commander Thach had spent a number of his 10-12 years of service as an airman as a gunnery instructor and when posted to a squadron as a commander he spent as much time as possible instructing his squadron in air to air gunnery, other squadron commanders might not have been as diligent or had the experience to train their squadrons as well.
Just about every nation did a poor job of training replacement pilots. Both German and British replacements in the BoB not haveing spent enough time in operational fighters let alone spent any real time in gunnery training (it is not learned in an afternoon.) 

British gunnery and bombing training during the 30s was often at annual (or at best semi annual) "camps" where the squadron/s left their home base/s and went to a base near the gunnery ranges for 1-2 weeks. They often went a year without firing guns. 

Please note this is no reflection on the pilots involved. If you are not given the training or opportunity to practice then the development of skills needed are only going to show up in a tiny percentage of the pilots who have, for some reason, an innate ability of understanding of the problem/s involved. 

The indictment is of the system/administrators rather than the pilots themselves. Given adequate training there is no reason to believe the British pilots were any worse than any other pilots.

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## kcomst (Dec 30, 2018)

There is one factor I haven't seen mentioned, although I haven't read the entire thread. It seems this discussion is focused on which is better: .303 vs .50 cal vs 20 mm. Some have mentioned how earlier in the war when there was less armament that the .303 worked better and later on the 20 mms were added. Each caliber has distinct advantages and disadvantages. Six .303 guns would be spewing a larger quantity of projectiles and so have a greater chance of hitting the target than .50 cal and even more than the 20 mm, but less impact per hit. If a pilot was a good shot, or as some practiced, waiting until they were close behind the enemy before pulling the trigger, then a few 20s might be better. The 50 seems to be a compromise between the two. Kind of like comparing #8 shot with #4 and buckshot. Other factors would be pilot skill and preference, the types of targets (air vs ground), speed etc. Why argue which one was best? Each platform was better at something than the other. Brits and Americans should not be arguing with each other over who was the greatest. We should be discussing why the Spitfire and Mustangs were better than the ME and FW, and why the ALLIES won the war over the AXIS powers. After all, the war of 1776 settled which country had the best military

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## tomo pauk (Dec 31, 2018)

kcomst said:


> There is one factor I haven't seen mentioned, although I haven't read the entire thread. It seems this discussion is focused on which is better: .303 vs .50 cal vs 20 mm. Some have mentioned how earlier in the war when there was less armament that the .303 worked better and later on the 20 mms were added. Each caliber has distinct advantages and disadvantages. Six .303 guns would be spewing a larger quantity of projectiles and so have a greater chance of hitting the target than .50 cal and even more than the 20 mm, but less impact per hit. If a pilot was a good shot, or as some practiced, waiting until they were close behind the enemy before pulling the trigger, then a few 20s might be better. The 50 seems to be a compromise between the two. Kind of like comparing #8 shot with #4 and buckshot. Other factors would be pilot skill and preference, the types of targets (air vs ground), speed etc. Why argue which one was best? Each platform was better at something than the other.



Fine so far, more or less.



> Brits and Americans should not be arguing with each other over who was the greatest.



Now where is fun if that is taken out from us children?



> We should be discussing why the Spitfire and Mustangs were better than the ME and FW, and why the ALLIES won the war over the AXIS powers.



We have had plenty of threads dealing with Spit vs. 109 or Pony vs. 190, at least my conclusion is that things are not that cut & dry, especially when comparison is made for different years/eras of ww2. 
We also have had discussions on comparing Allies vs. Axis logistics, war-making capability, money available etc.



> After all, the war of 1776 settled which country had the best military



French?

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## Kevin J (Dec 31, 2018)

kcomst said:


> There is one factor I haven't seen mentioned, although I haven't read the entire thread. It seems this discussion is focused on which is better: .303 vs .50 cal vs 20 mm. Some have mentioned how earlier in the war when there was less armament that the .303 worked better and later on the 20 mms were added. Each caliber has distinct advantages and disadvantages. Six .303 guns would be spewing a larger quantity of projectiles and so have a greater chance of hitting the target than .50 cal and even more than the 20 mm, but less impact per hit. If a pilot was a good shot, or as some practiced, waiting until they were close behind the enemy before pulling the trigger, then a few 20s might be better. The 50 seems to be a compromise between the two. Kind of like comparing #8 shot with #4 and buckshot. Other factors would be pilot skill and preference, the types of targets (air vs ground), speed etc. Why argue which one was best? Each platform was better at something than the other. Brits and Americans should not be arguing with each other over who was the greatest. We should be discussing why the Spitfire and Mustangs were better than the ME and FW, and why the ALLIES won the war over the AXIS powers. After all, the war of 1776 settled which country had the best military


I think you'll find that on the British side that there was a general reluctance to fight kith and kin with some high level resignations at the beginning so I don't think you were fighting our 'A' Team. After 7 years of war employing mainly German mercenaries and Indian allies, our parliament wasn't willing to spend any more money on it. Us Brits tend to call an end to most wars after about 7 years and negotiate. On a more serious note, I believe that in 1939 through to 1941 the 0.303 Browning was the best and most reliable weapon even though you needed a lot of them. After that, I'd say, 20 mm Hispano cannon are essential for taking down bombers and 0.5 in Browning's for fighter vs fighter combat. For the Brits that means we must have cannon rather than HMGs. At war's end, our continued use of 0.303's appears to me to be criminally negligent.


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## Clayton Magnet (Dec 31, 2018)

kcomst said:


> the war of 1776 settled which country had the best military


1812 settled that definitively

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## Clayton Magnet (Dec 31, 2018)

Kevin J said:


> After that, I'd say, 20 mm Hispano cannon are essential for taking down bombers and 0.5 in Browning's for fighter vs fighter combat. For the Brits that means we must have cannon rather than HMGs. At war's end, our continued use of 0.303's appears to me to be criminally negligent.


20mm Hispano was superior in fighter vs fighter engagements as well. By wars end, the .303 was almost completely relegated to secondary duties. The RAF standardized on 4 20mm Hispano as the primary fighter armament by 1941. Spitfires continued to carry 4 .303's in addition to the 2 20mm strictly because the thin Spitfire wing struggled with the extra 2 cannons when fitted. Although some did, like the Mk.VC


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## Kevin J (Dec 31, 2018)

Clayton Magnet said:


> 1812 settled that definitively



You're both wrong, Ireland has the best military. Fought its way to independence after 700 years of occupation. Tiny little nation. With the help of the EU beat the Brits in the BREXIT negotiations.


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## parsifal (Dec 31, 2018)

Kevin J said:


> You're both wrong, Ireland has the best military. Fought its way to independence after 700 years of occupation. Tiny little nation. With the help of the EU beat the Brits in the BREXIT negotiations.





I think Britain has beaten itself to death on that issue

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## parsifal (Dec 31, 2018)

wars of independence can be massively hard to beat. Look at Indonesia, Vietnam, Algeria, and whole bunch of other colonial wars and the problem sill start to come into focus

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## Clayton Magnet (Dec 31, 2018)

Kevin J said:


> You're both wrong, Ireland has the best military. Fought its way to independence after 700 years of occupation. Tiny little nation. With the help of the EU beat the Brits in the BREXIT negotiations.


I have recently watched "The Siege of Jadotville". Interesting moment in Irish history. 
The movie was good, whether or not it was accurate historically

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## Kevin J (Dec 31, 2018)

Clayton Magnet said:


> I have recently watched "The Siege of Jadotville". Interesting moment in Irish history.
> The movie was good, whether or not it was accurate historically


Yes, I've watched that too, it was good. Yes, the Irish were some of our best troops, once Ireland left, the Empire was doomed.


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## RCAFson (Dec 31, 2018)

In his book Carrier Fighters, David Brown discusses the harmonization pattern used on the Fulmar (and maybe Sea Hurricane?). IIRC, he states that initially they used an RAF pattern but later switched to an Admiralty Standard Pattern; there was no difference in the resulting kill rate but the ASP resulted in far fewer damaged and/or lost Fulmars from Bomber Defensive fire. IIRC, the ASP tried to created a bullet stream rather than a converging cone, with the result that bomber gunners were disabled at a much higher rate.

I don't have the book at hand, and it'll be a few days before I can read it again.


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## Greyman (Dec 31, 2018)

I've only seen the Admiralty pattern diagrams for the Martlet and they are pretty similar to the 'Spread' patterns that the RAF finally adopted mid 1942 (after their proponents had been fighting for their adoption since 1938).


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## Shortround6 (Dec 31, 2018)

kcomst said:


> There is one factor I haven't seen mentioned, although I haven't read the entire thread. It seems this discussion is focused on which is better: .303 vs .50 cal vs 20 mm. Some have mentioned how earlier in the war when there was less armament that the .303 worked better and later on the 20 mms were added. Each caliber has distinct advantages and disadvantages. Six .303 guns would be spewing a larger quantity of projectiles and so have a greater chance of hitting the target than .50 cal and even more than the 20 mm, but less impact per hit. If a pilot was a good shot, or as some practiced, waiting until they were close behind the enemy before pulling the trigger, then a few 20s might be better. The 50 seems to be a compromise between the two. Kind of like comparing #8 shot with #4 and buckshot.



Things get confused because the gun is not the entire weapon. The Projectiles are part of the weapon and the gun is part of the delivery system. 
Over the course of the war the projectiles for the .303 changed and the proportions of the projectiles used changed. The four .303s in a 1943 Spitfire were firing as many incendiary bullets per second as the eight guns of a BoB Spitfire. 

The US .50 also changed quite a bit from as has been mentioned earlier in the thread. 

The 20mm Hispano also used different projectiles as the war went on. Changing it's effectiveness even if the rate of fire stayed the same. Early HE ammo had fuses that were too sensitive and they went off on the skin of the aircraft. Impressive hole in the sheet metal but the really important stuff several feet inside was often undamaged. Latere fuses allowed the projectiles to get several feet inside before detonating. 
In the early part of the war, to get around the fuse problem, a portion of the 20mm ammo was fired without HE filler and with a steel plug instead of a fuse.Not quite an armor piercing projectile but it would go through a lot of structure. Later on they put incendiary material inside this projectile and hardened the nose cap. If the shell broke open inside the aircraft there was quite a bit of incendiary material being scattered about (about 10 times as much as the incendiary material in the US .50 cal M8 API bullet). 
A 20mm in the last few years of the war was a more effect weapon than a 20mm in the first year of use even with the same firing rate and muzzle velocity because the projectiles were more effective.

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## Mad Dog (Jun 22, 2019)

Kevin J said:


> At war's end, our continued use of 0.303's appears to me to be criminally negligent.


There is a continual insistence that rifle-caliber machineguns were just deadweight, that using them against fighters like the FW190 was akin to tickling them with a feather duster. I say this because there is plenty of evidence to the contrary. Consider for starters that - except for two confirmed Hurricane victories - all the RAF victories in the Battle of Britain were won with the .303 Browning. And that was with the relatively-ineffective loadings forced on the RAF in 1940 by a shortage of armor-piercing and semi-armor-piercing-incendiary (Dixon) ammunition. 
RAF eight-gun fighters were still shooting down Luftwaffe fighters and bombers - even models with better armor - well into 1941. An example is Douglas Bader, who thought that eight reliable Brownings was superior to even four Hispanos, and scored his last victories in 1941 in an eight-gun Spitfire Va serial _W3185_. 
Later in the War, Spitfires armed with two Hispano cannon and four Brownings had their Brownings loaded with just AP and SAPI, and they were still being effective against Luftwaffe aircraft in 1945. As an example, when 317 Squadron's Spitfire IXs met the latest Bf109Ks and FW190Ds on January 1st 1945 (during the Bodenplatte raid), examination of the wrecks of two of their victories showed they had been achieved _after_ the attacking pilots had run out of cannon ammunition, and all the damage was from .303 hits.
An even more illuminating example is the loss of two FW190As in Russia, shot down in a case of mistaken identity by a pair of Finnish I-153 biplanes! The Fins had a number of captured I-153s, all of which were re-armed with four Browning .303s to ease ammunition supply issues. They did not have the RAF's Dixon SAPI round, using the much less effective de Wilde ammunition, yet they still shot down both FWs in a single pass. This wasn't the only modern and well-armored fighter the Finnish I-153s scored, they also shot down at least one Russian Airacobra.
Six Commonwealth air gunners reached ace status using only the .303 Browning to defend their bombers. Air gunner Wallace McIntosh, an upper gunner in a Lancaster, scored eight victories against heavily-armored night-fighters with just two .303 Brownings.
Yes, the .50 Browning was better, and the 20mm Hispano was better still (if you could score a hit), but to say the .303 Browning was worthless or "criminally negligent" is obviously false.

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## pbehn (Jun 22, 2019)

Mad Dog said:


> There is a continual insistence that rifle-caliber machineguns were just deadweight, that using them against fighters like the FW190 was akin to tickling them with a feather duster. I say this because there is plenty of evidence to the contrary. Consider for starters that - except for two confirmed Hurricane victories - all the RAF victories in the Battle of Britain were won with the .303 Browning. And that was with the relatively-ineffective loadings forced on the RAF in 1940 by a shortage of armor-piercing and semi-armor-piercing-incendiary (Dixon) ammunition.
> RAF eight-gun fighters were still shooting down Luftwaffe fighters and bombers - even models with better armor - well into 1941. An example is Douglas Bader, who thought that eight reliable Brownings was superior to even four Hispanos, and scored his last victories in 1941 in an eight-gun Spitfire Va serial _W3185_.
> Later in the War, Spitfires armed with two Hispano cannon and four Brownings had their Brownings loaded with just AP and SAPI, and they were still being effective against Luftwaffe aircraft in 1945. As an example, when 317 Squadron's Spitfire IXs met the latest Bf109Ks and FW190Ds on January 1st 1945 (during the Bodenplatte raid), examination of the wrecks of two of their victories showed they had been achieved _after_ the attacking pilots had run out of cannon ammunition, and all the damage was from .303 hits.
> An even more illuminating example is the loss of two FW190As in Russia, shot down in a case of mistaken identity by a pair of Finnish I-153 biplanes! The Fins had a number of captured I-153s, all of which were re-armed with four Browning .303s to ease ammunition supply issues. They did not have the RAF's Dixon SAPI round, using the much less effective de Wilde ammunition, yet they still shot down both FWs in a single pass. This wasn't the only modern and well-armored fighter the Finnish I-153s scored, they also shot down at least one Russian Airacobra.
> ...


I agree. It may have been true that the RAF had trouble bringing down bombers with rifle calibre guns it is also true that a huge number of planes and crew made it back from the BoB but never flew again. Anything containing a human and lots of technical equipment is vulnerable to 8 machine guns, as I understand it the biggest problem was marksmanship and the distance pilots were firing from. Pilots who got in close didn't seem to have a problem.


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## PAT303 (Jun 22, 2019)

I've always shaken my head when I hear people say the .303's were not effective, if that's true what brought down all the Luftwaffe planes in the BoB, lets also not forget that 40% of all the Me109's involved in the battle were armed with only four 8x57 mausers. A 2 second burst of AP incendiary from four .303's into any engine/cockpit is not going to end well for the receiver.


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## PAT303 (Jun 22, 2019)

pbehn said:


> I agree. It may have been true that the RAF had trouble bringing down bombers with rifle calibre guns it is also true that a huge number of planes and crew made it back from the BoB but never flew again. Anything containing a human and lots of technical equipment is vulnerable to 8 machine guns, as I understand it the biggest problem was marksmanship and the distance pilots were firing from. Pilots who got in close didn't seem to have a problem.



When you think that young RAF pilots found themselves doing 300 mph at 20,000ft trying to shoot down young Luftwaffe pilots also doing 300 mph at 20,000ft with a great number having never left the family farm or worked outside their village it's amazing they managed hit anything.

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## pinsog (Jun 23, 2019)

I've never been a fan of rifle caliber machine-guns. That being said, there are 2 major things controlling the effectiveness of fighter weapons in combat 
1. shooting ability of the pilot 
2. tight bullet density or pattern on the target

Both of these have to be correct or the weapon will not be effective. 

For instance: There is a huge difference in the effectiveness of 8 303 machine-guns spread out across the wing of a Spitfire with the ridiculous spread out pattern used during the Battle of Britain and the 8 303 machine-guns of a Hurricane in 2 tight banks of 4 all focused at say 250 yards. I don't care if your Jimmy Thach in the Spitfire, if you aim your guns perfectly and only 1 will hit a Zero or Me109 at 100 yards then they are not going to be effective. Just the same, if you have 12 303's stuffed into the nose of a Whirlwind and you've never even shot a rifle or shotgun, don't know about lead, and all you have ever been taught is how to look pretty while flying formation then you are also going to be worthless. 

But if you have both of those things right, say Jimmy Thach in a Whirlwind at Midway with 8 303's in the nose, then the outcome would probably have been the same as it was historically. 
As much as I dislike 30 caliber machine-guns for ww2 fighters, I have always felt like there Whirlwind was badly armed do to the 60 round drums magazines its 20mm cannon were stuck with. Most of the reports I read on Whirlwind consisted of "pulled up behind JU88 and opened fire, got a few hits, ran out of ammo, target damaged". I think 8 303's all packed into that tiny little nose with a reasonable amount of ammo per gun would have been like using a mini-gun. At ranges under 300 yards you either miss it completely or you obliterate it.

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## Lefa (Jun 23, 2019)

Mad Dog said:


> An even more illuminating example is the loss of two FW190As in Russia, shot down in a case of mistaken identity by a pair of Finnish I-153 biplanes! The Fins had a number of captured I-153s, all of which were re-armed with four Browning .303s to ease ammunition supply issues. They did not have the RAF's Dixon SAPI round, using the much less effective de Wilde ammunition, yet they still shot down both FWs in a single pass. This wasn't the only modern and well-armored fighter the Finnish I-153s scored, they also shot down at least one Russian Airacobra.


Any evidence this story? I have not read or heard of such a thing and I didn't think that the Finns i-153 would have shot down Airacobra...
Also, Finns used the same caliber 7,62 as the Russians, why would they have changed the guns?


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## pinsog (Jun 23, 2019)

Lefa said:


> Any evidence this story? I have not read or heard of such a thing and I didn't think that the Finns i-153 would have shot down Airacobra...
> Also, Finns used the same caliber 7,62 as the Russians, why would they have changed the guns?


Anything can shoot down anything if you pop up within range. KI43’s in China shot down P47’s P38’s and even B24’s


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## Lefa (Jun 23, 2019)

pinsog said:


> Anything can shoot down anything if you pop up within range. KI43’s in China shot down P47’s P38’s and even B24’s



Yes, but i'm from Finland, and I never heard or read about such cases. In addition, Finnish i-153 planes were used for reconnaisance purposes, and no longer in the summer of 1944 when the Germans had FW-190 planes here.


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## fliger747 (Jun 23, 2019)

Against Japanese Fighters, would the .303 (8) been effective?


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## Greyman (Jun 23, 2019)

Accounts from both sides say it was very effective.


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## Mad Dog (Jun 24, 2019)

Lefa said:


> Any evidence this story? I have not read or heard of such a thing and I didn't think that the Finns i-153 would have shot down Airacobra...
> Also, Finns used the same caliber 7,62 as the Russians, why would they have changed the guns?


I have the date as 30th May 1943, and two FW190s from JG26 flying out of Siverskaya. The FWs had engaged some LaGG-3s and IL-2s over the Gulf of Finland and were returning when they were bounced by the Fins. Depending on the source, either both or one of the FW190s went down after one pass. The Finnish I-153s claimed an La-5 and two LaGG-3s in the area. Since the Fins didn't have any FW190s of their own it is understandable that they might mistake an FW190 for an La-5, though hard to imagine how they could mistake a radial-engined FW for an inline-engined LaGG-3. The Russians reported several LaGG-3s but no La-5s lost in the area that day.
I have an FW190-A4 "White 8" wknr 5802, flown by Lt. Reck of 7/JG26 shot down by a Finnish aircraft over the Gulf of Finland on that date. No identity for the second FW190 found.
Hakans Aviation Page mentions the Finnish I-153s as being "....re-armed, having four 7.70mm Browning M.39 machine guns, in place of the original Soviet ShKAS 7.62mm guns...." Regarding the P-39 victory, Hakans says: "....On 29 July a group of five I-153s from 1/TLeLv 16 led by luutnantti H. Härmälä clashed with two Soviet Airacobras from 773 IAP over Korpiselkä. During the ensuing combat between 19:10 and 19:15 one Airacobra was claimed as a damaged by kersantti Rinkineva (IT-31) at Loimola. Ten days later in a POW interrogation it was learnt that the Soviet aircraft had crashed and Rinkineva got a confirmed victory....."

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## Mad Dog (Jun 24, 2019)

pinehilljoe said:


> Were Browning M2 50s ever considered as armament for British planes?....


 The pre-War RAF got what it was given by the civil servants of Whitehall, who sometimes listened to the experts, but often didn't. The MoD tried many trials of different armament to replace the old Vickers .303. The .303 Colt-Browning Star machinegun used in the Hurricane and Spitfire was actually meant as a stop-gap until a suitable cannon could be developed. Even then, Ralph Sorley came up with a formula that insisted a minimum of eight .303 MGs were required. The MoD had tried the Vickers 25mm, the Oerlikon 20mm FFL, the 37mm COW gun, and even considered an air-cooled version of the Vickers .5, but none met their criteria for throwing a certain poundage of HE at a target in a two-second burst. The RAF could have had an air-cooled version of the Vickers .5 with SAPI and HE rounds in operation long before 1939.
The RAF and MoD did test an early version of the Browning .50, but were not impressed because it did not offer a big enough HE loading. The RAF's fighters were intended as interceptors for killing bombers, and the fashionable thinking of the day (thanks to the French) was that cannon were the way to go. The same thinking saddled the P-39 with the 37mm Oldsmobile M4 cannon. 
The MoD developed an unbreakable fixation with the French Hispano 20mm, ignoring all other tried-and-tested options, despite the gathering clouds of War. Hawkers made a pre-War version of the Hurricane for Belgium which carried four .52 FN-Brownings, but the RAF ignored the option. In the Summer of 1940, when the RAF realised they probably needed more punch for the average pilot to knock down a Heinkel 111 with one burst, the Hispano was still a piece of junk. It had unreliable feed from a small magazine, an HE round that was just as likely not to explode on hitting an enemy as it was to explode in the barrel, and no incendiary round nor tracer. They finally got a semi-decent version in the Hispano II in the Hurricane IIC in 1941, by which time the large fleets of Luftwaffe bombers they were intended for were heading off to Russia. Though the Hispano got better with time, it wasn't really good until the MkV appeared. By then, the Browning .50 had long since been perfected. 
One reason the RAF and MoD resisted the Browning .50 was Ralph Sorley's formula, and that stated that six .50 Brownings were the very _minimum_ required, with a preference for eight! That is why in 1940 the MoD wasted time asking for versions of the P-40 (and later the P-51) with the capability to carry Hispano cannon, insisted the F4F-4 had to carry six .50s, and is thought to be one of the reasons the P-47 got eight .50s. Once a thought becomes entrenched in the mind of civil servants, it is very hard to change.

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## PAT303 (Jun 25, 2019)

The .5 vickers was considered along with the .5 browning, both were deemed too heavy for the power they possessed, the reason the 20mm was the first choice. The .5 vickers had an effective AP round that could penetrate 18mm of armour at 100m but no effective explosive/incendiary round, same for the browning. Both ended up with ammunition copied from scaled up MkVII Dixon .303 rounds, for the vickers that was 1943. The .303's if loaded with appropriate ammunition and zeroed into a convergence at say 250 yards would be effective, unfortunately the widespread use of ball ammunition which is designed to tumble on impact doesn't make for good target penetration.

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## Clayton Magnet (Jun 25, 2019)

Mad Dog said:


> Though the Hispano got better with time, it wasn't really good until the MkV appeared. By then, the Browning .50 had long since been perfected.


The .50 Browning was perfected just as it became obsolescent as an air to air weapon

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## buffnut453 (Jun 25, 2019)

Mad Dog said:


> The pre-War RAF got what it was given by the civil servants of Whitehall, who sometimes listened to the experts, but often didn't. The MoD tried many trials of different armament to replace the old Vickers .303. The .303 Colt-Browning Star machinegun used in the Hurricane and Spitfire was actually meant as a stop-gap until a suitable cannon could be developed. Even then, Ralph Sorley came up with a formula that insisted a minimum of eight .303 MGs were required. The MoD had tried the Vickers 25mm, the Oerlikon 20mm FFL, the 37mm COW gun, and even considered an air-cooled version of the Vickers .5, but none met their criteria for throwing a certain poundage of HE at a target in a two-second burst. The RAF could have had an air-cooled version of the Vickers .5 with SAPI and HE rounds in operation long before 1939.
> The RAF and MoD did test an early version of the Browning .50, but were not impressed because it did not offer a big enough HE loading. The RAF's fighters were intended as interceptors for killing bombers, and the fashionable thinking of the day (thanks to the French) was that cannon were the way to go. The same thinking saddled the P-39 with the 37mm Oldsmobile M4 cannon.
> The MoD developed an unbreakable fixation with the French Hispano 20mm, ignoring all other tried-and-tested options, despite the gathering clouds of War. Hawkers made a pre-War version of the Hurricane for Belgium which carried four .52 FN-Brownings, but the RAF ignored the option. In the Summer of 1940, when the RAF realised they probably needed more punch for the average pilot to knock down a Heinkel 111 with one burst, the Hispano was still a piece of junk. It had unreliable feed from a small magazine, an HE round that was just as likely not to explode on hitting an enemy as it was to explode in the barrel, and no incendiary round nor tracer. They finally got a semi-decent version in the Hispano II in the Hurricane IIC in 1941, by which time the large fleets of Luftwaffe bombers they were intended for were heading off to Russia. Though the Hispano got better with time, it wasn't really good until the MkV appeared. By then, the Browning .50 had long since been perfected.
> One reason the RAF and MoD resisted the Browning .50 was Ralph Sorley's formula, and that stated that six .50 Brownings were the very _minimum_ required, with a preference for eight! That is why in 1940 the MoD wasted time asking for versions of the P-40 (and later the P-51) with the capability to carry Hispano cannon, insisted the F4F-4 had to carry six .50s, and is thought to be one of the reasons the P-47 got eight .50s. Once a thought becomes entrenched in the mind of civil servants, it is very hard to change.




Interesting criticisms given that the move to 20mm cannon was clearly the right choice given that every postwar fighter, with the exception of the F-86, moved to cannon armament. Yes, there were teething troubles but thus is the case with any new technology being adopted by any military.

As to the 50cal argument, as has been posted several times, the 1939-vintage version of the US 50cal was a very poor relative of the gun that matured into such a successful weapon by the end of 1942. The rate of fire of the earlier version was relatively low and there were numerous issues with reliability, particularly in wing installations. Also bear in mind that a change to 50cals would necessitate replacing the entire logistics chain from .303 to 50cal bullets and all the supporting infrastructure (tools, belts, boxes etc). That's no small undertaking to make and it would be a brave person to order such a change in 1939 given the perilous political situation with Germany. 

For all your griping about "civil servants", in reality the RAF leadership had a pretty good idea of the situation and, IMHO, made exactly the right calls. Yes, it would have been preferable to get cannon armament online sooner but, in the interim, the tried and trusted .303 did well enough through the first few years of WW2.

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## Shortround6 (Jun 25, 2019)

Clayton Magnet said:


> The .50 Browning was perfected just as it became obsolescent as an air to air weapon



Such is the nature of Air to air combat. One might say the 20mm Hispano was perfected just as it became obsolescent as an air to air weapon. 
The lighter, faster firing versions of the Hispano going into service just as the revolver cannon was being developed. Granted it took a while in peacetime to get the revolver guns sorted out. The US navy MK 12 might be the last Hispano derivative and they may have pushed a bit further than should (1000-1200rpm with a bit bigger case) 

and going backwards, several 7.5-8mm machine guns were perfected just as the world was moving to 12.7-13.2mm machine guns. 

And the modern 20-30mm cannon were perfected just as effective, somewhat reliable air to air missiles were introduced (another long torturous road).

The funny rating was not meant to be derogatory, just a quick way of saying that the whole situation was funny in a strange way.

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## Clayton Magnet (Jun 25, 2019)

In no way did I take it as an insult, I fully agree. Perhaps it has all gone full circle now, with the GSh-30-1 auto cannon maybe nudging out the bigger, heavier revolver cannons? Maybe not, but that Russian cannon is pretty impressive for what it is. 
The .50 Browning was a fine weapon, but it wasn't the war winner that the History Channel makes it out to be. It was effective enough, but its weight penalty somewhat negated its performance. Sure the Mk.II Hispano was a heavy weight as well, but had much better downrange effect relative to its size.

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## Lefa (Jun 26, 2019)

Mad Dog said:


> I have the date as 30th May 1943, and two FW190s from JG26 flying out of Siverskaya. The FWs had engaged some LaGG-3s and IL-2s over the Gulf of Finland and were returning when they were bounced by the Fins. Depending on the source, either both or one of the FW190s went down after one pass. The Finnish I-153s claimed an La-5 and two LaGG-3s in the area. Since the Fins didn't have any FW190s of their own it is understandable that they might mistake an FW190 for an La-5, though hard to imagine how they could mistake a radial-engined FW for an inline-engined LaGG-3. The Russians reported several LaGG-3s but no La-5s lost in the area that day.
> I have an FW190-A4 "White 8" wknr 5802, flown by Lt. Reck of 7/JG26 shot down by a Finnish aircraft over the Gulf of Finland on that date. No identity for the second FW190 found.
> Hakans Aviation Page mentions the Finnish I-153s as being "....re-armed, having four 7.70mm Browning M.39 machine guns, in place of the original Soviet ShKAS 7.62mm guns...." Regarding the P-39 victory, Hakans says: "....On 29 July a group of five I-153s from 1/TLeLv 16 led by luutnantti H. Härmälä clashed with two Soviet Airacobras from 773 IAP over Korpiselkä. During the ensuing combat between 19:10 and 19:15 one Airacobra was claimed as a damaged by kersantti Rinkineva (IT-31) at Loimola. Ten days later in a POW interrogation it was learnt that the Soviet aircraft had crashed and Rinkineva got a confirmed victory....."




I asked a little.
Airacobra is true, but Jg26 was't close that area at that time. 
JG26


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## Barrett (Jun 27, 2019)

IMO four .50s represented the optimum WW II fighter armament. I've crunched the numbers, using the P-51B/C and 51D as baselines. The 50% increase in D firepower only yielded 10% increase in lethality (credited kills among probables and damaged.) The FM-2 "Wilder Wildcat" reverted to the F4F-3's four-gun armament after the dash four's six (done at RN request, I believe). Some F4F-4 aces I knew said they kept the two outboards as "get me home insurance," including Joe Foss, Swede Vejtasa and George Wrenn.

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## pbehn (Jun 27, 2019)

Barrett said:


> IMO four .50s represented the optimum WW II fighter armament. I've crunched the numbers, using the P-51B/C and 51D as baselines. The 50% increase in D firepower only yielded 10% increase in lethality (credited kills among probables and damaged.) The FM-2 "Wilder Wildcat" reverted to the F4F-3's four-gun armament after the dash four's six (done at RN request, I believe). Some F4F-4 aces I knew said they kept the two outboards as "get me home insurance," including Joe Foss, Swede Vejtasa and George Wrenn.


True for air to air combat perhaps, but a 10% increase in kills/damaged is huge for a marginal increase in cost and weight. For attacking ground targets which the P-51 was also used for the more the better.


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## swampyankee (Jun 27, 2019)

Barrett said:


> IMO four .50s represented the optimum WW II fighter armament. I've crunched the numbers, using the P-51B/C and 51D as baselines. The 50% increase in D firepower only yielded 10% increase in lethality (credited kills among probables and damaged.) The FM-2 "Wilder Wildcat" reverted to the F4F-3's four-gun armament after the dash four's six (done at RN request, I believe). Some F4F-4 aces I knew said they kept the two outboards as "get me home insurance," including Joe Foss, Swede Vejtasa and George Wrenn.



Four 0.50" M2 being the best choice is not something that the USN or USMC believed during WW2; the USN rated the 20 mm Hispano (when it worked) as roughly three times as effective as the 0.50" M2. The FM-2, the hotrod Wildcat, was also not being used significantly in fighter-fighter combat in the ETO. Indeed, I suspect had the US been able to reliably produce the 20 mm, the 0.50" would not have been specified on any post-war fighter.


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## Shortround6 (Jun 27, 2019)

End of the war/post war the Navy went for the 20mm cannon exclusively. 
I don't believe any NEW navy fighter was "_ordered_" after Oct or Nov of 1944 with .50 cal guns. Older fighters were certainly delivered after that date with .50 cal guns. The McDonnell FH-1 Phantom may have been the last fighter design to use the .50 cal for the Navy. 

The Army developed a split personality. Fighters got .50s. Bomber destroyers/night fighters/all weather fighters got 20mm guns.

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## Mad Dog (Jun 29, 2019)

Lefa said:


> I asked a little.
> Airacobra is true, but Jg26 was't close that area at that time.
> JG26


I've since found the event in Donald Caldwell's _The JG26 War Diary Volume Two 1943-1945_, on page 91. Caldwell says the two pilots were a Hauptman Kelch and a Leutnant Reck, with Kelch making it back to Silverskiya in one piece. So, not two FW190s lost to two I-153s armed only with Browning .303s, but one definitely was.

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## tomo pauk (Jun 30, 2019)

Barrett said:


> *IMO four .50s represented the optimum WW II fighter armament. * I've crunched the numbers, using the P-51B/C and 51D as baselines. The 50% increase in D firepower only yielded 10% increase in lethality (credited kills among probables and damaged.) The FM-2 "Wilder Wildcat" reverted to the F4F-3's four-gun armament after the dash four's six (done at RN request, I believe). Some F4F-4 aces I knew said they kept the two outboards as "get me home insurance," including Joe Foss, Swede Vejtasa and George Wrenn.



(my bold)
Hello, 
Is the bolded remark equally worth for non-American air forces/services?


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## fastmongrel (Jun 30, 2019)

tomo pauk said:


> (my bold)
> Hello,
> Is the bolded remark equally worth for non-American air forces/services?



4 x .50s would be less than adequate for downing a B17 or HE177.


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## PAT303 (Jun 30, 2019)

I'd be happy with 4x .303 and 2x 20mm, I'd load the .303's with tracer/incendiary and use them to get the right deflection/lead angle, a quick flick of the thumb as soon as I saw the ''flash'' of a hit and the SAPI's would be on their way, all hypothetical of course but that would be my choice.


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## Mad Dog (Jun 30, 2019)

Greyman said:


> _"It is a fair bet that the Air Staff rejected this option on the ground that 'If this is what the Americans are doing, it is almost certainly wrong'._
> Citation needed on that one. Where's that eyeroll emoji?.


Yes, but it was a similar viewpoint that resisted the adoption of submachineguns for the British Army, especially the proven Thompson M1928, because they were "gangster guns"! When, in 1938, the Air Ministry ordered the American and quite excellent Lockheed Hudson for coastal patrols, there was equal uproar, with letters to the Times accusing the Air Ministry of "treason".


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## Mad Dog (Jun 30, 2019)

fastmongrel said:


> 4 x .50s would be less than adequate for downing a B17 or HE177.


But the Allies didn't really have to worry about the HE177 because they tended to catch fire by themselves! Indeed, the most common Luftwaffe day bomber the Western Allies faced from 1941 onwards was the Junkers 88, for which four .50 Brownings was more than adequate and six was ample.


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## pbehn (Jun 30, 2019)

Mad Dog said:


> But the Allies didn't really have to worry about the HE177 because they tended to catch fire by themselves! Indeed, the most common Luftwaffe day bomber the Western Allies faced from 1941 onwards was the Junkers 88, for which four .50 Brownings was more than adequate and six was ample.


This is pure hind sight. Until the decision was made by the RAF to switch to cannon the LW was making as much progress as the UK and USA was. RAF pilots armed with rifle calibre guns were "alarmed" to say the least at the destructive power of German cannon.


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## Mad Dog (Jun 30, 2019)

pbehn said:


> This is pure hind sight.....


 Well, yes and no. The Air Ministry had already specified the Hispano 20mm as the "ideal" bomber-killer, but they already had intelligence that the Luftwaffe was concentrating on building tactical bombers like the Heinkel 111 and Junkers 88. Goering was a numbers man, and he argued he could build two tactical bombers for the price in time and materials as a four-engined strategic bomber. That was great as long as the Wehrmacht just needed the Luftwaffe to supply tactical support, but a real problem when the problem was one of strategic bombing. General Weaver was the only man in the early Luftwaffe with the interest in strategic bombing and really in a position of power to influence matters. When he died so did the Ural Bomber. The poor Heinkel 177 was cursed by Goering's love for dive-bombing and the DB606 "twinned" engine. By the time the idea was properly resurrected in 1942, in the Amerika Bomber project, it was already too late for the over-stretched German aircraft industry. MI6 had long been aware of the economic problems facing Germany pre-War, which is one of the reasons many in Whitehall simply failed to believe that Hitler would go to war in 1939. Hence, no need to worry about a German equivalent to the B-17.


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## pbehn (Jun 30, 2019)

Mad Dog said:


> Well, yes and no. The Air Ministry had already specified the Hispano 20mm as the "ideal" bomber-killer, but they already had intelligence that the Luftwaffe was concentrating on building tactical bombers like the Heinkel 111 and Junkers 88. Goering was a numbers man, and he argued he could build two tactical bombers for the price in time and materials as a four-engined strategic bomber. That was great as long as the Wehrmacht just needed the Luftwaffe to supply tactical support, but a real problem when the problem was one of strategic bombing. General Weaver was the only man in the early Luftwaffe with the interest in strategic bombing and really in a position of power to influence matters. When he died so did the Ural Bomber. The poor Heinkel 177 was cursed by Goering's love for dive-bombing and the DB606 "twinned" engine. By the time the idea was properly resurrected in 1942, in the Amerika Bomber project, it was already too late for the over-stretched German aircraft industry. MI6 had long been aware of the economic problems facing Germany pre-War, which is one of the reasons many in Whitehall simply failed to believe that Hitler would go to war in 1939. Hence, no need to worry about a German equivalent to the B-17.


If the non aggression pact had continued or Hitlers invasion of Russia had been successful all previous bets and intelligence are "off".


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## pinsog (Jun 30, 2019)

PAT303 said:


> I'd be happy with 4x .303 and 2x 20mm, I'd load the .303's with tracer/incendiary and use them to get the right deflection/lead angle, a quick flick of the thumb as soon as I saw the ''flash'' of a hit and the SAPI's would be on their way, all hypothetical of course but that would be my choice.


By the time you see the flash of your 303’s on the enemy plane and press the button for your 20mm the firing solution will have already changed and the 20mm will miss.

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## Mad Dog (Jun 30, 2019)

pbehn said:


> If the non aggression pact had continued or Hitlers invasion of Russia had been successful all previous bets and intelligence are "off".


 Too true! But then Hitler didn't have to invade Poland either. He could have avoided war with France and Britain by using his allies in south-eastern Europe such as Romania to attack Russia, or invaded via Finland. Invading Poland set up a confrontation with the Allies. Invading the USSR via Romania would probably have brought quiet support from the UK at least, though the French probably would have got a bit hysterical. So, let's imagine Hitler doesn't invade Poland in 1939, he waits until May 1941 and invades the USSR from Finland and Romania. There is no Mediterranean campaign because Italy would never have gone to war. The attack on the USSR doesn't threaten the British Empire, it actually promises to remove an enemy of the Empire. Poland would be ambivalent because it would be quite happy to see the USSR defeated. Britain might even sell Germany the long-range bombers to do the Ural Bomber role when the Luftwaffe realised they needed them. No combat losses from Norway and the Low Countries or the Battle of Britain, no three week delay due to the Greek campaign. I'd say Germany would have taken Moscow easily, especially if Hitler could persuade the Japanese to attack the USSR instead of Pearl Harbor.

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## Kevin J (Jun 30, 2019)

Mad Dog said:


> Too true! But then Hitler didn't have to invade Poland either. He could have avoided war with France and Britain by using his allies in south-eastern Europe such as Romania to attack Russia, or invaded via Finland. Invading Poland set up a confrontation with the Allies. Invading the USSR via Romania would probably have brought quiet support from the UK at least, though the French probably would have got a bit hysterical. So, let's imagine Hitler doesn't invade Poland in 1939, he waits until May 1941 and invades the USSR from Finland and Romania. There is no Mediterranean campaign because Italy would never have gone to war. The attack on the USSR doesn't threaten the British Empire, it actually promises to remove an enemy of the Empire. Poland would be ambivalent because it would be quite happy to see the USSR defeated. Britain might even sell Germany the long-range bombers to do the Ural Bomber role when the Luftwaffe realised they needed them. No combat losses from Norway and the Low Countries or the Battle of Britain, no three week delay due to the Greek campaign. I'd say Germany would have taken Moscow easily, especially if Hitler could persuade the Japanese to attack the USSR instead of Pearl Harbor.


It was all about oil, just like today. The Caucasus had oil. The East Indies had oil. The Germans and the Japanese had none.

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## Mad Dog (Jul 1, 2019)

Kevin J said:


> It was all about oil, just like today. The Caucasus had oil. The East Indies had oil. The Germans and the Japanese had none.


 True, but the Germans did have the Romanian oilfields, and if they had not had to fight the Western Allies, they could have concentrated on capturing the Caucasus oilfields. If they had captured Baku, and had strategic bombers to destroy the remaining Soviet oilfields in the Urals, then the Soviets would have been the ones desperate for fuel. It does beg the interesting question; if the West was not at war with the Nazis, would the USA ship fuel to the Soviets?


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## Kevin J (Jul 1, 2019)

Mad Dog said:


> True, but the Germans did have the Romanian oilfields, and if they had not had to fight the Western Allies, they could have concentrated on capturing the Caucasus oilfields. If they had captured Baku, and had strategic bombers to destroy the remaining Soviet oilfields in the Urals, then the Soviets would have been the ones desperate for fuel. It does beg the interesting question; if the West was not at war with the Nazis, would the USA ship fuel to the Soviets?


We did ship fuel to the Soviets, but it was aviation fuel. The Nazi's lost because they were Nazi's. Perhaps a better way for the Germans to have become the masters of Europe would have been through trade.

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## Todd Secrest (Jul 1, 2019)

Kevin J said:


> We did ship fuel to the Soviets, but it was aviation fuel. The Nazi's lost because they were Nazi's. Perhaps a better way for the Germans to have become the masters of Europe would have been through trade.


Perhaps a better way? 
Germany has become the master of Europe thru trade, it's from all the money Germany has made selling higher priced BMW, Mercede, Audi, Porsche cars to rich people in the USA and Volkswagens to the masses of the world.

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## Kevin J (Jul 1, 2019)

Todd Secrest said:


> Perhaps a better way?
> Germany has become the master of Europe thru trade, it's from all the money Germany has made selling higher priced BMW, Mercede, Audi, Porsche cars to rich people in the USA and Volkswagens to the masses of the world.


Correct. I call the EU, the Fourth Reich.

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## Lefa (Jul 1, 2019)

Mad Dog said:


> I've since found the event in Donald Caldwell's _The JG26 War Diary Volume Two 1943-1945_, on page 91. Caldwell says the two pilots were a Hauptman Kelch and a Leutnant Reck, with Kelch making it back to Silverskiya in one piece. So, not two FW190s lost to two I-153s armed only with Browning .303s, but one definitely was.



I asked Juha, if anyone knows, hi knows.

"Prien and partners Die Jagdfliegerverbände der Deutschen
Luftwaffe Teil 12 / III is also found info in lost list, Reck shot down by the Finns I-153, but Brewster 239 in the text in reports.
Also, I looked at those claims, Finnish shot down 1 La-5 and 2 LaGG-3
by the Brewsters, Wind and Vesa. "

Means that time that area, there is two Brewster. It is therefore very unlikely that I-153 would have made it. 

And i still wonder the change from 7.62 to 7.7mm.
7.7 is not the standard of the Finnish army. 

Off course is possible, we have 12 pc Hurricane, Cladiators etc.


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## PAT303 (Jul 1, 2019)

pinsog said:


> By the time you see the flash of your 303’s on the enemy plane and press the button for your 20mm the firing solution will have already changed and the 20mm will miss.



Plenty of real gun camera footage on youtube of planes being taken under fire and tracers walking onto the target and then the pilots taking quite a few seconds to react once they do start taking hits, which is more than enough time.


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## tyrodtom (Jul 1, 2019)

PAT303 said:


> Plenty of real gun camera footage on youtube of planes being taken under fire and tracers walking onto the target and then the pilots taking quite a few seconds to react once they do start taking hits, which is more than enough time.



Almost all that gun camera film you watch on U-Tube is shown in slow motion, hardly realistic.


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## Shortround6 (Jul 1, 2019)

It was done, it was sometimes advocated, it sometimes worked, doesn't mean it was really a good idea. Particularly for the Spitfire. you had 12 seconds of firing time for the 20mm (once they got belt feed on the Vc) and around 17-18 seconds firing time for the .303s. Pull that .303 sighter trick very often and you run out of .303 ammo before the 20mm guns run out. 

Then you have the problem of the different times of flight of the 20mm and .303 ammo. The 20mm ammo comes out of the muzzle about 16-17% faster than the .303 and the big shells don't slow down as quickly so the difference in time of flight only increases with range. Throw in that the _average _human reaction time is just under a 1/4 of a second and a 300mph airplane will have moved just over 100 ft in that time alone and you start seeing that the technique doesn't really gain all that much.

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## Glider (Jul 1, 2019)

I think an obvious point. The average pilot had few opportunities to get a good shot at an enemy aircraft, when the chance came you let fly with everything you had. Real war isn't a simulation, if you get the chance, then you take it. 
I have read a couple of reports where a crew was up against a pilot who first fired with one type of weapon and then with the rest. All these crews had the same thought, 's___t we're in trouble, it's an expert'.


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## pinsog (Jul 1, 2019)

Trying to boresight an enemy plane especially a fighter with one weapon, seeing hits then firing another weapon that has a totally different velocity and trajectory seems like a waste of time. If he is close enough that trajectory doesn’t matter then you shouldn’t need to use the light guns to boresight him. If he’s far enough away you need to use light guns to boresight him then the trajectory comes into play. All the while he’s moving and maneuvering. If he’s a fighter then he’s gone, if he’s a big bomber then you should shoot everything at once because he’s a big target. If your strafing you only have a couple of seconds to fire anyway so you use everything

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## PAT303 (Jul 1, 2019)

Shortround6 said:


> It was done, it was sometimes advocated, it sometimes worked, doesn't mean it was really a good idea. Particularly for the Spitfire. you had 12 seconds of firing time for the 20mm (once they got belt feed on the Vc) and around 17-18 seconds firing time for the .303s. Pull that .303 sighter trick very often and you run out of .303 ammo before the 20mm guns run out.
> 
> Then you have the problem of the different times of flight of the 20mm and .303 ammo. The 20mm ammo comes out of the muzzle about 16-17% faster than the .303 and the big shells don't slow down as quickly so the difference in time of flight only increases with range. Throw in that the _average _human reaction time is just under a 1/4 of a second and a 300mph airplane will have moved just over 100 ft in that time alone and you start seeing that the technique doesn't really gain all that much.



Your shooting anyway regardless of what guns you have, you may as well pull onto the target using the 17-8 seconds of 303's before toggling the switch to the 20mm's to finish the job, if you run out of ammo but destroy the target that's good enough for me. Reading up on the aces, they all used the same tactic, get in close, hit hard and get away, the time of flight between both types of ammunition is a mute point if shooting within say 250m using that technique. Furthermore, I feel the idea of the enemy plane moving out of the way or the pilot reacting to all this is overstated somewhat considering that the whole scenario would be over in a matter seconds, as discussed on another thread, something like 80% of pilots that were shot down didn't see or know they were under attack until it was too late.


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## pbehn (Jul 1, 2019)

PAT303 said:


> . Furthermore, I feel the idea of the enemy plane moving out of the way or the pilot reacting to all this is overstated somewhat considering that the whole scenario would be over in a matter seconds, as discussed on another thread, something like 80% of pilots that were shot down didn't see or know they were under attack until it was too late.


True but also true that the vast majority of ammunition fired never hit anything.

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## PAT303 (Jul 1, 2019)

Which is why I'd do it my way, I've been shooting my whole life yet I still need a bit of practise to get my eye in if I shoot clays, deflection shooting isn't easy, it's a very hard skill to master.

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## Todd Secrest (Jul 1, 2019)

I'm going to make a guess that the Spitfire's wings were originally designed to hold four .303 machine guns (each), 1930s thinking, 
And switching over to Browning M2 .50 and it's ammo (at a later date) would increase the weight of the Spitfire, slowing it down, reducing climb rate and increasing the turn radius, so staying with the .303 would give the Spitfire a better chance of getting it guns on target in the first place.
Later on when the Merlin engine's power was increased and the 20mm cannons became more reliable, it would have then made more sense to upgrade the Spitfire with 20mm cannons.

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## jmcalli2 (Jul 4, 2019)

Clayton Magnet said:


> The RAF essentially skipped the step to heavy machine guns, and standardized on cannons as soon as possible. Something that took the AAF and later the USAF about 10 more years to do.
> 
> "A Hurricane armed with 4 or 6 M2s would have been formidable in bringing down Heinkels."
> Keep in mind that the standard US fighter armament in 1939/40 was one .50 supported by one or two .30's.




The problem as I understand it was gun reliability; the US version of the 20mm HS was subject to jamming much more than the .50cal was. The English did a better job of building the HS so it didn't jam as much.


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## Barrett (Jul 5, 2019)

I'd hoped to include Shortround's illuminating comments on page 5 in this response but have been unable to make that option work.

Anyway: ref. K14 and other computing sights. They required a smooth touch on "the handlebars" and IIRC 2 seconds or more tracking to yield a solution. For that reason many pilots, including some aces, left them locked in "pegged range." Gabby said that Jerry Johnson was the best shot in the 56th because he'd attended an RAF gunnery course that included a gyro sight in a Spit. "Jerry saw the huge lead that you needed in a full deflection shot."


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