British .303 vs 50 Cal M2

[pinsog]

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

 

[Shortround6]

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.

 

[pinsog]

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)

 

[Clayton Magnet]

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.

 

[pinsog]

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.

 

[Shortround6]

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.

 

[Clayton Magnet]

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

 

[pinsog]

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.

 

[Shortround6]

Or that yes,

at least the job/s the US needed doeing

 

[pinsog]

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.

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?

 

[Clayton Magnet]

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

 

[pinsog]

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

 

[Shortround6]

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?

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.

 

[Greyman]

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.

 

[swampyankee]

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)

I believe it's the first.

 

[Greyman]

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.

 

[Shortround6]

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.

 

[Greyman]

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.​

 

[fastmongrel]

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.

 

[pbehn]

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.