0.50 Browning MG and it's descendnats for 'other' air forces?

[Shortround6]

I don't think the British were interested in 100-200 round boxes. You're in just as bad or worse of a position than with the Vickers K - once you factor in trying to reload.

I have documents on the efforts to beef up the armament on many British planes, and in all of the wires/letters back and forth between and amongst the ministries/firms involved the supply of Brownings is never the issue.

Thank you, I may be corrected, however what are the dates of the documents? The .303 Browning shortages that I am referring to are mostly (or entirely) pre-war. The time of the introduction of the first Spitfires, the first Gladiators, Blenheim Is and such. By the Fall of 1939 and later the production may have been increased enough to cover the majority of needs, especially with the K gun covering the minor uses so shortages were no longer an issue. I know that at least two British companies built .303 Brownings and there may have been more (or sub contracting) and/or purchases from over seas? Some of the early Blenheims and Battles got Lewis guns because the K gun was not in production yet.

What is being proposed here is introducing a 4th gun ( Browning .303, Vickers K gun, Hispano, +?) into the "mix" or replacing the Hispano and doing it in the 1937-39 time frame.From a manufacturing point of view, if England is just barely making enough Brownings in 1937-39 ( regardless of what they did later) then trying to introduce a "new" gun is only going to cause delays in the guns that were made.

 

[Shortround6]

He definitely wasn't planning to get .5-in Brownings into his bombers and have them operating in long-range, unescorted, daylight missions. But there were many cases where his aircraft did operate in daylight and he wanted them to have the heavier armament.

But then it doesn't really change much in the outcome of the war does it? A few lower losses on a few specialized missions? Important to the crews that took part. Perhaps important to Harris in building bomber command or the perception of bomber command ("look at what Bomber Command can do, all you politician that allocate money") but not important to the overall outcome of the war. Are twin .50 tail and top turrets in place of quad .303 turrets really going to change the loss rates that much?

 

[Timppa]

Commander of the Fighter Squadron 24 , G.Magnusson wrote a memo after the Winter War, Spring
1940:
"With 4 .30 Browning machine guns with ball rounds it was difficult to shoot down enemy bombers.
Later, with incendiary and AP bullets, the SB's and DB's could be flamed with 200-300 rounds.
These results were improved when all four machine guns were converged to 150 metres.

This armament was satisfactory against bombers, but against fighters it was too weak due to bullets deflecting from the strong seat armor.

To operate succesfully in the future we should definitely switch to heavier calibre machine guns
or, if possible, to 20-23mm hub cannon. This armament would be effective, regardless of the enemy planes are faster or slower than ours."

 

[Greyman]

Are twin .50 tail and top turrets in place of quad .303 turrets really going to change the loss rates that much?

Probably not, but who knows? It's not just applying the upgraded armament to what Bomber Command did - but also thinking of all the instances of what they would have done differently had they had the armament.

For example, there was one colossal Anglo-American daylight mission to Berlin planned when the Germans were in full retreat in the West in a hope to panic the German Government at a critical moment. Harris:

'General Doolittle came up to Bomber Command on the afternoon before the projected attack and he and I and our staffs examined the final plan together in the Operation Room. The routes were pretty well cut and dried and when I discovered that the Americans, whose long-range fighters were required to protect Bomber Command's striking force as well as their own Fortresses, were unable to raise enough fighters to give what I considered adequate cover for our aircraft during such a deep penetration of Germany.

...

There had been some misunderstanding about this in the earlier stages of planning the operation, since it was only on the day before the operation was to take place that I discovered that an American long-range fighter force was insufficient to cover both out own and the American bombers all the way to Berlin was not available.

Although Jimmy Doolittle did his utmost, as always, to meet our requirements I had to refuse to subject my force to a risk far greater then usual - I had particularly in mind our obsolete .303 calibre defensive armament - the whole operation was therefore cancelled.'

Also, to characterize Bomber Command's daylight efforts as 'a few specialized missions' is missing the mark by quite a bit.

 

[Koopernic]

If the practices of German night fighter aces is to be believed the 303 was effective. If the night fighter was discovered by the bomber and subjected to fire the policy of an experienced pilot was to break of the attack and seek another quarry. It was better to live and to fight another day than to subject yourself aircraft and crew to such risk. The 303 was often observed to give accurate return fire out to 800 meters.

The nature of a night fighter attack is different of course, it's a much slower approach, and most bombers shot down apparently did not see the attack coming. However if seen, say in moonlight the 303 was adequate.

The use of 3cm blind fire radar radar in the rear turrets of allied bombers would have been a temporary advantage since ultimately a night fighter with a 75cm radar dish and 4-6 2.0cm canon is going to beat two 0.5 inch Brownings aimed by a 30cm dish. The progression of proposed gun stations for the Lancaster appears to have been the elimination of guns in the tail, with only the gunner seated there, now in a fixed position, with an enlarged radar dish. A pair of 20mm Hispano guns in a ventral and dorsal positions would then be used to provide a very credible fire power in terms of range and destructive capability.

German work on blind fire radar had gun back to the very inception of its Liechtenstein series of radars. These radars used horizontal and vertical lobe switching to indicate the direction of a detected target and gave a surprisingly accurate indication of whether the target was dead ahead and as the German Navy and the ground based guns were already using blind fire and lobe switching it was an obvious candidate. The systems carried names such as "Pauke SD" and would have been able to centre a target, for some reason it never came in to use. However the use of microwaves allowed compact dish antenna and the same techniques as AAA radar and all allied and German nigh fighter radar would have had this ability by end of 1945. The USN actually had it before then. The kinds of ranges and firing times now would benefit from a much longer ranged bigger gun.

The USA in its bombers such as the B47 and most early B52 continued to use the 0.5 probably appreciating its compactness in the rear gun station where it was important to have streamlining and room for as many sensors as possible. The appearance of the 20mm Gatling style mechanism seems to be what finally swung the US solidly into the 20mm camp where it has remained to this day.

 

[yulzari]

Anecdotal evidence is, of course, not itself evidence but I do recall an ex Bomber Command Lancaster rear gunner telling me that he and his crew regretted the twin 0.5" turret introduction as they felt that the role of the gunner was to frighten a night fighter into breaking contact and x4 tracers looked far worse at night than x2. Hitting the night fighter was thought to be incidental and he used to arrange for his belts to be all tracer whatever the powers that be may have wanted.

On the .303" Browning shortage; surely every new weapon is in shortage when first introduced until production churns out enough to go around?

 

[Greyman]

Anecdotal evidence is, of course, not itself evidence but I do recall an ex Bomber Command Lancaster rear gunner telling me that he and his crew regretted the twin 0.5" turret introduction as they felt that the role of the gunner was to frighten a night fighter into breaking contact and x4 tracers looked far worse at night than x2. Hitting the night fighter was thought to be incidental and he used to arrange for his belts to be all tracer whatever the powers that be may have wanted.

Yeah the tactics ran the full gambit, I'm sure. I read one anecdote where a bomber 'skipper' told his gunners that he would shoot them himself if they ever fired their guns - not wanting to give their position away whatsoever and survive solely through evasive action. The main fear being that night fighters could be operating somewhat in pairs and even as you were driving off one fighter another could be closing in using your tracer as a guide.

 

[Edgar Brooks]

The .303 Browning shortages that I am referring to are mostly (or entirely) pre-war. The time of the introduction of the first Spitfires, the first Gladiators, Blenheim Is and such..

I'd be interested to know the source of that information, since nobody, that I've spoken to, has ever heard of it, and there's no mention in any of the official files.
70 (only) Gladiators had Lewis, Vickers Mark III/V, or Vickers "K" guns (with Browning guns thereafter,) and all 70 were delivered in early 1937, long before the first service Spitfire was delivered to 19 Squadron in August 1938. Test aircraft had to be flown with a full complement of guns, and then delivered in the same way, or the CoG could be compromised. It also seems strange that the Hurricane apparently wasn't included in this drama.
The Rose turret was a direct result of Village Inn, a system of radar detection from the rear turret, plus infra-red recognition of following aircraft, plus the gyro gunsight. This also led to the removal of tracer, since the gunsight "aimed off" for the gunner, so that it was hoped the nightfighter pilot would never know what hit him.

 

[Shortround6]

I'd be interested to know the source of that information, since nobody, that I've spoken to, has ever heard of it, and there's no mention in any of the official files.
70 (only) Gladiators had Lewis, Vickers Mark III/V, or Vickers "K" guns (with Browning guns thereafter,) and all 70 were delivered in early 1937, long before the first service Spitfire was delivered to 19 Squadron in August 1938. Test aircraft had to be flown with a full complement of guns, and then delivered in the same way, or the CoG could be compromised. It also seems strange that the Hurricane apparently wasn't included in this drama.

Which is it? No "shortage" or 70 Gladiators fitted with Lewis and Vickers guns?

The "story" such as it is, is on page 93 of "Flying guns of World War II". I say "such as it is" because some people seem to making more of it than it really deserves. BSA reached a production schedule of 600 guns per week in March 1939. They peaked at 16,390 for the month in March 1942. It is really so hard to believe that in 1937 or mid 1938 production of the Browning was not quite up to speed to equip ALL new aircraft?

Fighter aircraft are often flown without guns, in some cases they need ballast to maintain the CG and in some cases they do not. Any Spitfires delivered without the full eight guns were soon fitted with them in the field and well before the war started. In some cases flight tests were done on unarmed planes carrying ballast to represent armament.

The premise of this thread is what countries could have used the .50 cal Browning, or versions of it, starting in 1938/39. In England's case they were just getting the .303 Browning into service and production at that time and trying to get the Hispano started up. Useful as a 3rd gun might have been (or not) it could only come at the cost of delays in the existing .303 Browning and Hispano programs and was not something the British could afford at that time.

 

[Greyman]

Found another tidbit, for what it's worth:
By July 1939 the Air Ministry estimated that 15,000 to 20,000 Brownings had been issued to the Service.

 

[kool kitty89]

Which you can't do, because the Air Ministry wanted armour-piercing and explosive in the same round.

And the potential for explosive/incendiary in 13-15 mm rounds wouldn't cut it? Let alone cause a re-think of the cancelled Mk.V incendiary round of the .303. (too complex/costly to use a fuze on the smaller round, but -prior to the Mk.VI- may have been more attractive on a larger caliber projectile).

Aside from that, there's the primary argument of these sorts of threads hinging on the powers that be (UK or any other government in question here) thinking/making decisions differently. I for one tend to prefer to try to avoid hindsight outright for motivation, and focus on potential reasonable/rational incentives for choosing differently.

From a practical standpoint there's 3 major ways to destroy enemy aircraft: killing the pilot/crew (requiring armor penetration or selective angles of attack), igniting fuel tanks (requiring incendiary ammunition and/or explosive), or causing critical structural failure by hitting an ammunition magazine, major structural components or concentrated damage to load-bearing minor components, control surfaces/mechanics, hydraulics, or damage to engine, oil or coolant radiators, coolant/oil or fuel tanks substantial enough to cause rapid draining of fluid. Some of those may be armor protected as well, so aside from tearing holes big enough to circumvent sealing, there's the matter of armor penetration. Aluminum is also generally non-sparking, but aircraft with steel structural components could potentially act as ignition sources for AP ammunition, same for strikes to the engine resulting in fire.

Pilot/crew vulnerability is relatively limited even without armor, so ability to cause crippling damage ANYWHERE on the aircraft's structure is significant.

Because they were able to get a licence agreement with the owners of the Hispano to build it here, in specially built factories, ensuring that there would be no interruption of supply.

Any that license was easier to obtain than the one for the .303 browning or Oerlikon? The British at very least were using import Oerlikon FFS cannons, if not having a domestic license (I'm unsure of the specifics), but that seemed a rather pointless gun to try as an alternative to the Hispano given the weight and recoil advantages were modest and rate of fire was much lower. (the FFF or FFL would have made much more sense, especially the latter if they wanted decent armor penetration as well -FFF might be more interesting in defensive arrangements, but standardized production of fewer distinct types would probably favor the FFL)

Aside from that, the browning adapted to a larger round (more so rechambered for a more powerful round, while the simpler barrel/ammunition change would make more sense for smaller militaries, but would still be a quicker adaptation) would be the other alternative and the one more relevant to this thread.

Either way limiting the number of new guns in production (and to lesser extent, being explored for acceptance into production) would be a concern as well. Considerations for replacements for the .303 in both fighter AND defensive armament positions would be a consideration as well, and effective ability to not only produce a gun but have it reliable and practical to install on existing aircraft (or those about to enter service) would also be significant. (the FFF and FFL, while not able to be synchronized, may still have been practical to fit underwing on the Gladiator, and certainly be much easier to adapt to the Spitfire and Hurricane -and any defensive mounting- than the Hispano)

And, with "slower firing" you've immediately blown it, since the consideration had to be on getting as much hitting power in one or two seconds as possible. How many aircraft were fitted with the Madsen, incidentally? The Ministry files never mention it.

Given the 23 mm madsen packed about double the damage per round, the 'hitting power' would have been about the same, provided you're not firing on a rather light/weak aircraft. (in which case the .303 batteries would be preferable anyway)

The USAAC (and possibly USN) are the only air forces I'm familiar with seriously considering and testing the 23 mm Madsen. It was planned for use on the P-38, P-39, and tested in underwing fairings on the P-36. Plans to adopt it were canceled after the fall of Denmark as they seemed to be relying on import purchase rather than licensed production (or in any case, had failed to secure a license by that time). The much heavier, much slower firing 37 mm M4 cannon was then substituted on both the P-38 and P-39. (though both had already had the M4 slated as an alternative or competing weapon and the primary choice of Bell who'd previously used it on their Airacuda)

If nothing else, the Madsen ammunition should have been appealing and seriously considered for adapting the Hispano to. (rechambering it or necking out the 20x110 mm cartridge)

There may have been difficulties securing licenses from Madsen, and the US and UK hadn't adopted their 20 mm AA gun either. (still odd the Germans didn't get use out of the 23 mm madsen, or adapting the round to one of their own weapons)

 

[kool kitty89]

Edgar Brooks has a point.

It is also a true that the 'Air Ministry' tried to use technical wizardry (pretty low tech to be sure) to compensate for for poor training and less than ideal gun sights. Pointing many guns in different directions to compensate for poor aim is hardly compatible with fewer guns that are more effective on an individual basis.

That sort of logic may have also contributed to their very different feelings towards concentrated nose armaments, synchronized or otherwise, and the lack of hub cannon provisions on the Merlin. (that change alone would have made the Hispano seriously more useful and practical, especially as a high-precision weapon for pilots with exceptional aim)

Centerline armaments still allow the option to spread for pilots that understand the variety of tactics available. Provided they KNOW the aiming difficulties in play, applying a slight amount of cross controlling or rudder drift to spread the area of fire would be a practical option too. (not the same as the shotgun effect of huge wing batteries, but also more flexible in allowing the pilot some choice of when to use it, granted doing that on the vertical axis would be bad on early Merlin aircraft without compensation for negative-G)

Though that said, having a combination of wing AND nose armement allows both a compromise and better spread of fire. A 3 cannon armament would have been plenty useful and perhaps ease adoption and practical use of the Hispano a fair bit. (but that arrangement would be useful for the Oerlikon and Madsen guns as well -or Hispano rechambered for 23 mm)

However we also have to consider that the British barely had enough .303 Brownings to go around. Or perhaps they didn't have all that they wanted and used substitutes to some extent. In 1940 they certainly didn't have enough of the better types of .303 ammo that they wanted. Given that little fact, trying to make hundreds of thousands of little shells with fiddly little fuses seems a complication they didn't need at the time. During the BoB many eight gun fighters were flying with only one gun loaded with De Wilde ammunition. It had only gone into mass production in the spring of 1940. Scaling it up to suit various 11-18mm schemes in 1935-39 would have needed a time machine.

Part of this discussion is seriously considering the Browning mechanism in general (M1919 included) earlier on, but hardly limited to British service.

The Madsen and Oerlikon guns have a number of advantages over the Hispano, aside from the less attractive FFS. The FFL and FFF in nose or wing mountings and the Madsen in nose and (maybe) later adapted to stiffer wings, but probably not as practical pre-war. The FFF is really only attractive for cases where the moderate weight and recoil increase of the FFL is unattractive, both are far more practical to use on most aircraft of the late 1930s than the Hispano. (and weighing the cost/benefit of further developing the oerlikon guns for higher rate of fire vs scaling the Hispano down to a lower powered cartridge and lighter weight/recoil -though the British Mk.I and Mk.II Hispano's RoF advantage over the FFL was more modest at 600 vs 500 RPM vs the higher RoF for the earlier -heavier- French HS.404 at 700 RPM)

It took time to sort out the fuses even on 20mm ammo, early Hispano fuses acted too quickly and exploded on the skin of the aircraft which limited the structural damage and damage to components and items further inside the plane. This was enough of a problem that inert training ammo with steel caps were issued as a "ball" round, no explosion but the kinetic energy was formidable.

A soft core cannon shell would indeed be more useful in leu of problematic HE ammunition, and the same goes for ball or AP ammo with incendiary tip. The mushroomand fragmentation effects of ball type soft ammo wouldn't tend to punch straight through softer components, but expand/fragment and do a good deal more damage. (albeit for the few steel tubing based frames, it might be less useful -against aluminum stressed skin construction it'd work better -hard/AP ammo might do more damage to something like the hurricane's fuselage ... plus incendiary ammo would be very effective at igniting any nitrocellulose doped fabric -flame retardant dopants would be another matter, but I think one of the hurricane and Gladiator's problems early war was highly flammable doped fabric along with wooden stringers being used)

Rolls Royce did design a MG that in one version use the .55 cal Boys round. However it took them too long (they seem to have been distracted by other things and by the time it was ready it was a. not really wanted and b. they were being told to concentrate on designing and building better engines.

If they didn't use the browning as the basis for the weapon, adapting the M2 Browning mechanism to that round would seem much more straightforward. (pushing it to higher pressures and velocities might be more of a problem, but adapting it to the larger projectile with the .55 Boys matching the cartridge dimensions of the .50 BMG already, it would be more a matter of limiting propellant load until structural reinforcements were completed -any mixed armaments still including the .303 would better match the lower velocity round anyway)

Aside from that, the .303 itself was retained in spite of its somewhat mediocre performance compared to 8 mm Mauser and .30-06 round due to volume production and substantial back inventory from what I understand, along with existing guns using it. Otherwise some modest improvement to even the light machine guns should have been possible by adopting different ammunition. (directly adopting the American M1919, ammunition and all would have given at least a modest boost to firepower due to the higher muzzle energy and slightly higher RoF)

The Air ministry made a fairly practical logistical decision in that regard, and I'd tend to agree with that one being reasonable on the whole a great deal more than the fixation on the Hispano. (particularly a wing-mounted hispano -or Oerlikon FFS)

Given the weight and overall performance I'd tend to think the Oerlikon FFF would be preferable to the Vickers .50 or Browning chambered for the same round, but the RoF and velocity of the latter might have been better. (depending how you view the drum armament of the FFF) The Vickers gun had jamming/reliability issues of its own, but perhaps less unreasonable in a defensive mounting where the mechanism can be reached and cycled/cleared. (plus it could have been adopted earlier than not only a hypothetical vickers-browning but earlier than the .303 browning was, at least historically)

 

[kool kitty89]

I would note that in the thinking of the time, it was thought that 2-3 seconds was all the firing time a pilot would have on one firing pass so the Hispano offered at least two and possibly 3 firing passes even with the drums.
It also took a lot longer to sort out the belt feeds than originally thought. They changed from pulling on the rims to get the rounds out of the belt to pushing on the noses (not really a good idea with nose fused HE ammunition) to pulling on the rims again.

The 20mm Hispano lasted 14 years in British service before starting to be replaced by the 30mm Aden cannon so it could hardly be said to be a bad bargain or investment. Adopting some sort of interim gun in 1937-38 would have just meant adopting the Hispano at a later date and a waste of money and time.

Would a developed Oerlikon FFL really not have been similarly useful? (with potential to be belt fed and reach at least 750 RPM at lower weight and recoil) Or a Hispano or Browning (or improved Madsen) derivative firing the very useful 23 mm madsen ammunition. (having closer merits to the post-war 30mm ammo)

Or, for that matter, switching to 30 mm outright before the end of the war using a browning, oerlikon, or hispano derivative. (the Japanese had some really nice 30 mm designs and the MK 108 was pretty close to what the British shifted to post war, if only it had shifted to a lighter round with higher velocity, the Japanese guns were closer to what the British ended up wanting, though)

The shortage of Brownings rarely applied to fighter guns (at least once the shooting started, a few Spitfires were initially delivered with only 4 guns and were fitted with the full eight when already issued to service squadron/s, a few early Gladiators were fitted with Lewis guns under the wing until they could be replaced by Brownings) or fixed forward firing guns, but Some planes (like Blenheims and Hampdens) may have soldiered on a bit too long with Vickers K guns for rear defense instead of Brownings. Likewise Wellington waist guns. The Vickers K gun did OK but it could have been replaced by the Browning in many cases if more Brownings had been available. Some planes got Lewis guns in 1937-38 because there weren't enough Vickers K guns to go around. Early Blenheims had a single Lewis gun in the turret (which only traversed 180 degrees). The British did manage to keep things moving along and few, if any planes had to fly without some sort of gun in a position where there was supposed to be one but the British didn't have any surplus of .303 Brownings. Futzing about with oddball alternatives wasn't going to improve things.

In the cases where drum/pan magazines were preferred, shortages of the Vickers K being replaced with the Lewis gun would make some sense, but in cases where belt feed was preferred and the browning was in short supply, wouldn't the Vicker's .303 gun make sense? (the jamming issues would be poor for wing mounts or cowl mounts with inaccessible breeches, but for flexible mounts it seems more reasonable -and the .50 vickers likewise) The .303 Vickers had a lower RoF than the Vickers K though, but higher than the Lewis gun and, again, we're talking situations where belt-feed is preferred.

And, again, where drum feed was prefered in flexible mounts, the Oerlikon guns should have been serious considerations. (either the FFF or FFL, the former in the same weight class as the .5 Vickers and more reliable, plus available earlier than any hypothetical .50 vickers-browning -the FFL would be more directly competitive with the .50 BMG itself or a 13.2 mm, and probably lighter than a .55 adaptation, plus the smooth recoil would allow for more stable aiming, especially for flexible mounts rather than powered turrets)

As for ammunition - I can't cite any specific tests, but from documents on discussions/correspondence within the RAF it seems that the large use of .303 ball rounds early in the war was due to the belief that .303 AP rounds were more easily deflected from aircraft skin/structure coupled with general lack of armour on enemy aircraft at the beginning of the war.

I'd think the AP rounds would have more an issue of punching straight through soft components without doing much damage, while ball rounds would tear larger holes in the skin and have greater likelihood of hitting control cables (or rods), hinges, hydraulic linkages, or potentially puncture fuel tanks. (and potentially tear larger holes in self-sealing tanks)

Many countries could have used Brownings or Browning derived guns to advantage given unlimited factory space/capability. British could have found a .5in Browning (Japanese Ho-103) rather useful as a defensive weapon as the Hispano didn't fit well in turrets. However the change would NOT have allowed the 4 engine heavies to operate any better by day and would not have changed the overall strategy or tactics of the airwar.

Italians could have used them but then we are back to factory space. Italians would have had to tool up before WW II.

Aside from potential browning derivatives, with the likes of the Madsen and Hispano rather heavy and powerful, it really seems like the Oerlikon FFF and FFL should have been the guns of choice for mid 1930s progression beyond LMG armaments, at least for un-synchronized configurations. The German MGFF modification might have been a bit better off if it'd retained the lighter projectiles of the FFF itself (rather than the lower velocity, heavier german round). The MG-FF itself ended up nearly as heavy as the FFL and significantly lower velocity.

 

[Edgar Brooks]

Which is it? No "shortage" or 70 Gladiators fitted with Lewis and Vickers guns?

Don't split hairs; 70 in early 1937, followed by all the rest produced that year, plus all of those up to August 1938 (and the Spitfire's inception)plus all of the Hurricanes apparently having 100% fit of Brownings does not sit well with this story of shortages.

The "story" such as it is, is on page 93 of "Flying guns of World War II". I say "such as it is" because some people seem to making more of it than it really deserves. BSA reached a production schedule of 600 guns per week in March 1939. They peaked at 16,390 for the month in March 1942. It is really so hard to believe that in 1937 or mid 1938 production of the Browning was not quite up to speed to equip ALL new aircraft?

It is when nobody, to my knowledge, has ever mentioned it, for example, in "British Aircraft Armament" R Wallace Clarke states only that 460,000 guns were manufactured in the U.K., plus spares for another 100,000, and doesn't even hint at any supposed shortages.
Please remember that it was you who introduced the subject, so it's hardly surprising that those of us, ignorant of the story, want to know more.

 

[Shortround6]

It is when nobody, to my knowledge, has ever mentioned it, for example, in "British Aircraft Armament" R Wallace Clarke states only that 460,000 guns were manufactured in the U.K., plus spares for another 100,000, and doesn't even hint at any supposed shortages.

Talk about splitting hairs, BSA alone built the 460,000 guns with spares for another 100,000 but they didn't do it in 1937/38 did they?

What part of "shortage in 1937/38" are you not getting? It certainly doesn't mean a shortage for the rest of the war. There are often temporary shortages as production starts up of certain items which go away as production gets going.

They built over 57,000 Hercules engines, doesn't mean in wasn't in short supply at times (Beaufighter IIs and Wellington IIs).

There were shortages (temporary) of all sorts of things as the British (and most other nations) geared up in 1937-38-39. It doesn't mean the shortages lasted for entire war or even a large part of the war.

One only has to look at the rear gun/s in the Blenheim to realize something was going on. Starting with a single Lewis gun (hardly state of the art even in 1936 but better guns were not in production yet) it went to the Vickers K gun, then two Vickers K guns, A single Browning showed up somewhere and twin Brownings and finally a whole new turret with two widely spaced Brownings. Granted this took around 5 years. Whitleys got 4 Brownings in the tail but a single Vickers K gun in the forward turret. I can see how arguments could be made could be made using the Vickers gun on pedestal mounts, ring mounts, ball mounts or swing mounts. It gets a little harder to make the case in a turret where the ammo supply (or at least 200-600 rounds) can traverse with the gun/s.

 

[Greyman]

One only has to look at the rear gun/s in the Blenheim to realize something was going on. Starting with a single Lewis gun (hardly state of the art even in 1936 but better guns were not in production yet) it went to the Vickers K gun, then two Vickers K guns, A single Browning showed up somewhere and twin Brownings and finally a whole new turret with two widely spaced Brownings. Granted this took around 5 years. Whitleys got 4 Brownings in the tail but a single Vickers K gun in the forward turret. I can see how arguments could be made could be made using the Vickers gun on pedestal mounts, ring mounts, ball mounts or swing mounts. It gets a little harder to make the case in a turret where the ammo supply (or at least 200-600 rounds) can traverse with the gun/s.

Again, the pre-war use of Lewis/Vickers free guns had nothing to do with shortages of Brownings and all to do with choices made by the powers that be. The continued use of inadequate defensive armament was due to the time it took to design, manufacture and distribute conversion sets for the additional armament.

In the case of the Lewis, the decision wasn't made to completely replace it with the Vickers until the latter had been in service for a year or so and its marked superiority was evident.

Ironically enough as I go through my material on all of this I do see numerous concerns for the supply of the Vickers GO gun - including Vickers having to cancel work on an aerodrome-defence gun in order to produce the required number of 'K' guns once the decision was made to 100% replace the Lewis.

 

[Shortround6]

And the potential for explosive/incendiary in 13-15 mm rounds wouldn't cut it? Let alone cause a re-think of the cancelled Mk.V incendiary round of the .303. (too complex/costly to use a fuze on the smaller round, but -prior to the Mk.VI- may have been more attractive on a larger caliber projectile).

As a general rule of thumb the weight of the of the projectile varies with the cube of the caliber. This assumes similar construction, materials and shape. A 13mm projectile will be roughly 4 times heavier than a 8mm projectile and a 20 mm projectile will be 4 times heavier than a 13mm projectile or 16 times heavier than an 8mm projectile. Simple theory gets thrown several curves (complications) in that the 8mm projectiles often have sizable components of lead in them while the larger ones do not. Steel having a rather lower density than lead. HE and pyrotechnical compounds have a much lower density than either. Wall thickness of the hollow projectile doesn't scale well. You need a certain minimum thickness for strength, both for centrifugal force (projectile spin) and to keep the pressure on the base of the projectile when firing from buckling the projectile in the barrel. This means, for practical purposes until the German mine shell, that projectile capacity did NOT change with the cube of the diameter but increased at a much faster rate. You don't need a much thicker shell wall on a 20mm projectile than you do on a 13-15mm projectile.

Any that license was easier to obtain than the one for the .303 browning or Oerlikon? The British at very least were using import Oerlikon FFS cannons, if not having a domestic license (I'm unsure of the specifics), but that seemed a rather pointless gun to try as an alternative to the Hispano given the weight and recoil advantages were modest and rate of fire was much lower. (the FFF or FFL would have made much more sense, especially the latter if they wanted decent armor penetration as well -FFF might be more interesting in defensive arrangements, but standardized production of fewer distinct types would probably favor the FFL)

a lot depends on timing, at certain times the Oerlikon guns required lubricated ammo (read greased or at least wax coated) which was frowned on for aircraft use. Grease/wax at 60 degrees F vs Grease/wax at minus 30-40 degrees let alone 60 degrees below. What is tolerated aboard ship/s is not tolerated as much in aircraft or on land. Please remember that while war was looming they weren't shooting just yet and what was desirable often held more importance than it did once the shooting started. Different countries may have had different standards of reliability.
Please remember too, that in the case of Great Britain, they were not buying just for use in the British isles but for use through out the Empire. ANY gun or ammo had to tolerate a wide range of climatic conditions.

Aside from that, the browning adapted to a larger round (more so rechambered for a more powerful round, while the simpler barrel/ammunition change would make more sense for smaller militaries, but would still be a quicker adaptation) would be the other alternative and the one more relevant to this thread.



If nothing else, the Madsen ammunition should have been appealing and seriously considered for adapting the Hispano to. (rechambering it or necking out the 20x110 mm cartridge)

There is a lot of talk about re-chambering and necking out (or down). Some of these guns had a few MM to spare as far as overall cartridge length goes and some did not. The designation, such as 23 X 106 does not tell you the over all length of the round, it tells you how long the cartridge case is without projectile. It also does not tell you haw fat the case is (diameter of the body of the case). It sometimes tells you how the gun was headspaced (how the cartridge is located in the chamber front to back) The 20mm Hispano case was 24.8mm in diameter and headspaced on the shoulder. This is what caused a lot of grief with the US guns. The US built guns had a chamber that was a bit too long and allowed the round to "float" a bit. If the chamber is too short the breech block cannot close all the way and the gun should not fire. If too long the breech block will close and the firing pin will hit the primer, however if the cartridge is not held in a controlled manner, rim at the back or shoulder on case hitting shoulder on chamber, the case can move forward when hit by the firing pin with the effect of a light strike and a dud round bringing firing to a halt until the round can be ejected from the gun and a new one chambered.
The Russian 23 X 115 round was 27mm in diameter through the body and the Madsen round was 29mm through the body. The Russian 20 ShVAK round was only 21.8mm though the body but had a 25.2mm rim on the back.

Some guns worked a bit different and used a massive extractor (and spring) engaging the rim of the case to hold it against the bolt face. Some breech blocks were locked against the barrel at the moment of firing pin strike and some were not (blow backs) and some guns were set up so that there was a bit of delay between the cartridge firing and extraction starting, (chamber pressure dropped some before case started to move rearward) the blow backs depended on inertia and spring tension for the delay. Some guns used bolt accelerators, once the bolt/breechblock had moved a small distance and broken the case loose from the chamber walls it accelerated to a higher speed for the rest of it's travel.

The taper on the .50 cal Browning case is there for a reason, so is the shoulder. They can be changed but eliminating them or reducing them to mere vestiges of what they were is going to play havoc with the guns ability to function without some major development time.

 

[tomo pauk]

...
Aside from potential browning derivatives, with the likes of the Madsen and Hispano rather heavy and powerful, it really seems like the Oerlikon FFF and FFL should have been the guns of choice for mid 1930s progression beyond LMG armaments, at least for un-synchronized configurations. The German MGFF modification might have been a bit better off if it'd retained the lighter projectiles of the FFF itself (rather than the lower velocity, heavier german round). The MG-FF itself ended up nearly as heavy as the FFL and significantly lower velocity.

Looks like the Oerlikon FFF fired a 128 g shell at 600 m/s, the Ikaria MG FF fired the 134 g shell at same speed? The muzzle energy was 23-24 kj. For a 100 g projectile, that would be close to 700 m/s? The MG FFM used a bit smaller propellant charge, the 92 g shell went out at 700 m/s.
The MG FF didn't ended nearly as heavy as the FFL, but FFL received more development that gradually decreased it's weight from 43 to 34 kg, later to 30 kg. The development of the FFF/MG FF wasn't much pressed on, the only modification being the MG FFM, so the lower recoil could still operate the gun action. The FFL would be as easy/hard to install on the turets as MG 151 or Hispano V?

Since there is a violent opposition for the UK adoption of the 'big bang' Browning ( ), any opinion on how well would it served in LW or USAF/USN?

 

[Edgar Brooks]

What part of "shortage in 1937/38" are you not getting?

The "38" part (and there's no need to be rude); Gladiators built in early 1937 had other guns fitted, while Gladiators built in mid/late 1937 and the whole of 1938 had Brownings fitted, as did all Hurricanes, and the first Spitfires in August that year. However much I try, I cannot equate that with this supposed shortage in 37/38; 37, yes, but 38, not a chance.

It certainly doesn't mean a shortage for the rest of the war

Who mentioned the rest of the war? I certainly didn't, but simply pointed out that another (British) book, on armaments, makes no mention, whatsoever, of any shortage of Brownings at any time.

 

[Jabberwocky]

The Gun was made by FN in Belgium Pre-war and they may have gotten a higher rate of fire out of it. Considering the trouble the Americans had getting it to 1200rpm any claims of prewar FN guns firing that fast in service must be viewed with suspicion.

The FN-Browning was variously advertised at rates of 1000 rpm, 1050 rpm, 1100 rpm and 1200 rpm throughout the 1930s, so I wouldn't view the rate with too much suspicion. The most common figure I've come across is the pre-war literature is 1050 rpm, which is the rate the RAF got when they tested the gun in 1938.

I would consider 1200 rpm to probably be the upper end of the cyclic limit for the gun. A maximum value, rather than an average value.

The Finns also put a locally built version of the M2 Browning on their Brewster Buffalos and the VL Myrsky. The gun is recorded in Finnish sources as firing at 1000-1100 rpm, further lending credence to the notion that the Browning was capable of being uprated to more than 1000 rpm.

I think the Romanians put the FN-Browning on their IAR 80/81 as well. Dropped it from the design due to lack of guns, if I recall correctly.