What was the air to air weapon, or combination of weapons, used in WWII?

The recent Spitfire XIV v P51D thread wandered for quite a while into the merits (or otherwise) of the Browning .303 used by the RAF throughout the war as opposed to the .50 beloved of the USAAF and USN. To broaden that discussion, what was the best air to air weapon of WWII? I'm talking out of historical context here – what single weapon type could best fulfil all the tasks faced by the various fighters of WWII; heaver bomber interception, fighter v fighter, the lot. Or alternatively, which fighter had the combination of weapons that could best cover all the bases. 4 X 20mm Hispanos? Eight X .50 brownings? Russian, American or Italian? Plenty of grist for the mill here…

It depends on the type of enemy you are fighting.

Look at the evolution of the Luftwaffe fighters. When the Luftwaffe was on the offensive the armament was typically lighter. As the war progressed and Germany was having to combat the heavy bomber formations, the armament became more heavy. Of course more powerful engines probably had an influence as well.

.303 and .50 are just fine for dealing with fighters.

Basically I don't think there is a definative answer to this question.

DerAdlerIstGelandet said:

It depends on the type of enemy you are fighting.

Look at the evolution of the Luftwaffe fighters. When the Luftwaffe was on the offensive the armament was typically lighter. As the war progressed and Germany was having to combat the heavy bomber formations, the armament became more heavy. Of course more powerful engines probably had an influence as well.

.303 and .50 are just fine for dealing with fighters.

Basically I don't think there is a definative answer to this question.

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Undoubtedly, different armaments were used for different tactical situations throughout the war. 8x.303s were adequate for fighter vs fighter situations in the BoB, and marginal for bomber interception, whereas the German 30mm was better in the latter role than the former. What I'm thinking is, would one weapon set have done both jobs, if not as well, at least passably well? A quartet of Hispano 20mm a la Hawker Tempest perhaps, or the eight 'point fifties of the P-47? Or maybe tha La-7's trifecta of Russian 23mm? And what were the relative merits of those guns, or for that matter the various .50/12.7mm weapons fielded by the various powers?

Tony Williams has done an exceellent study on this issue. The linkis below

WORLD WAR 2 FIGHTER GUN EFFECTIVENESS

Basically it wasnt just the mission that affected the best armament, it was also sometimes the pilots. Having a larger number of smaller weapons is better when your pilots are not as experienced. Heavier armament tends to be larger calibre, that in turn usually means a slower rof. Having a slower rof means you will generally need more deflection when shooting and this in turn required a higher skill level on the part of the shooter.

LMGs tended to be too light to hurt more heavily protected targets. Heavier cannon, like 30mm+ teneded to increase drag, weight and ammunition supply. They of course tended to affect performance as well.

IMO the best all round mix of armament was 4 x 20mm cannon. Good firepower, and range , but not so much weight and drag as to seriously affect performance.

Who made the vest cannon? Id say the germans, whilst the US made the best HMGs. Id say the Brits were probably the best at fitting LMGs into the wings of fighters

Tony Williams also did an article on the idea WW2 fighter armament:

IDEAL WW2 FIGHTER ARMAMENT

For those to lazy to read the article, his conclusion was that an ideal weapon for all but heavy bomber targets was a 20 mm cannon similar to a lightened Hispano Mk V, with electric priming and a sped up RoF (750 to 1000 rpm), firing slightly smaller and lighter ammunition (105 g vs the Hispanos 130 g shell), not too disimilar to a more streamlined German Minengeschoss round. Best mounting was in the wing roots, avoiding problems with harmonisation for wing guns, engine mounting with radials/some inlines and aerodynamic problems with cowl mountings. The cost is a 10% drop in RoF with electric priming.

Personally, I believe the best LMG was the ShKAS (just shading the MG 17), best HMG was the UB 12.7 mm (Belgian FN Browning deserves a mention, despite the limited combat it saw), best 20 mm cannon is a tie between the Hispano Mk V and the B.20 and the best cannon over 20 mm was the MK 108.

The Germans developed the best 20 mm + cannon ammunition with the thin walled Minengeschoss round for various calibers. The US developed the best HMG ammunition with the M8 API, although the Soviet API ammunition for the UB runs a VERY near second AND it was available several years earlier and the Italian and Belgian 13.2 mm HE rounds also deserve mention. Best LMG ammunition is a bit of a wash, although the DeWilde/Dixon ammunition for the .303 Browning deserves a mention, as does the Soviet 7.62 API and the b-patrone ammunition for the 7.92 x 57 guns.

If I was going into combat, I'd want the Soviets designing my weapon, the Germans designing the ammunition and the installation, the US building and supplying it and the RAF servicing it and keeping it running.

parsifal said:

Tony Williams has done an exceellent study on this issue. The linkis below

WORLD WAR 2 FIGHTER GUN EFFECTIVENESS

Basically it wasnt just the mission that affected the best armament, it was also sometimes the pilots. Having a larger number of smaller weapons is better when your pilots are not as experienced. Heavier armament tends to be larger calibre, that in turn usually means a slower rof. Having a slower rof means you will generally need more deflection when shooting and this in turn required a higher skill level on the part of the shooter.

LMGs tended to be too light to hurt more heavily protected targets. Heavier cannon, like 30mm+ teneded to increase drag, weight and ammunition supply. They of course tended to affect performance as well.

IMO the best all round mix of armament was 4 x 20mm cannon. Good firepower, and range , but not so much weight and drag as to seriously affect performance.

Who made the vest cannon? Id say the germans, whilst the US made the best HMGs. Id say the Brits were probably the best at fitting LMGs into the wings of fighters

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I was tending towards the 4 x 20mm formula myself; quick enough to hit fighters, big enough to hurt heavy bombers. But how did Hispanos stack up against the Russian Shvak or German MG151? I've read some claims that the Shvaks were the best of the lot. And I think the Germans were making some pretty hot ammunition for their guns towards the end of the war, significantly upping its hitting power.
Re the Browning .50, wasn't the German 12.7 a bit lighter and with a slightly higher ROF? Were the Italian Bredas any good?
I'm more of a general knowlege kind of bloke than a techno-freak, so I'm happy to listen to more motivated individuals in these matters.
One other related question - where did the P-47 get its reputation for enormous fire power? Surely the RAF always had at least one cannon armed fighter in the line-up with more punch, before and after the 47 appeared.

Not an expert in thbis field, but I believe the Germans had explosive 20mm shells with enhanced ballisticsm, at least at the end.

Shvaks were not that good. They fired a lightweight shell, and had an rof below that of the German and allied equivalents.

Jabberwock, too me not a expert but i think that the "chemical" content of UB API ammo is larger of that of M8 API and UB had also HE and HEI ammos.

Parsifal, Shvak 20mm afaik is one of higher ROF 20mm of WWII

However that only works with twin engine aircraft such as the Fw-187.

My second choice would be 1 x 3cm Mk108 cannon firing through the prop shaft. One hit does about as much damage as 4 x 20mm shells. Good only for close range but that's where most WWII era aerial kills were achieved. The Mk108 cannon has more killing power per pound of weight then any other WWII era fighter weapon. So even lightweight and dirt cheap aircraft such as the Me-109 and He-100 can pack a huge punch.

Hello, Dave,
For a fighter that can accept 4 cannons in the nose (but 23mm cannons), please see La-9

My choice would be all Soviet, thank you , even above 20mm bracket. With VJa 23 and NS-37 (if yours Shvaks are deemed as of too light a punch), one really has it all. P-38 with 4 VYas, in 1942, hmm...

Shvak was indeed firing one of the lightest shells, but it was doing it at high RoF (800 vs 600 of the Hispano II), and it was available way before any other belt fed 20mm cannon. Plus it was able to be synchronized, unlike the Hispanos (so a workable fighter with just 2 cannons was feasible good enough, not hampered with possible jamming of one of the cannons). Admittedly, the Mg-151/20 was the best package of the bunch, once introduced, up until B-20 was in town (enabling even the tiny Yak-3 to accept 3 of those in the fuselage).

added: being a necked up 12,7mm cartridge, Shvak's ammo took up the same volume for same number of rounds as it was the case for the Soviet 12,7mm rounds - enabling the Shavk to carry far more rounds, for the same allocated volume, than it would be possible for Hispano. (Too bad the Americans did not gave their .50s the same treatment of up-necking, it would've saved us of many internet debates )
So, yes, Shvak was one great cannon.

davebender said:

4 x 20mm in the nose. However that only works with twin engine aircraft such as the Fw-187.

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Didn't the La-9 have 4 nose mounted cannon's?


EDIT: Ahhhh, Tomo beat me to it.

The 30 cal MG was not ideal or even adequate for dealing with fighters. The various 50 cals were. Probably the best all around weapon for air to air and air to ground including all AC was a reliable fast firing 20MM.

I agree. For Soviet aircraft it was an excellent choice.

Need to add that the 20MM cannon should have good velocity and good ammo capacity. The early war 20MM cannon in the Zeke had neither and was outclassed by the 50 BMG. I suspect the early 20MM in the BF109 was the same.

Bear in mind we are shooting at aircraft 200 meters away. Large HE payload is more important then velocity at that distance.

Not necessarily true that ranges are 200 yards. USN taught that fire was opened at 300 yards in full deflection runs and it you read Lundstrom there are many cases where Wildcat pilots opened fire in excess of 300 yards. It is my opinion that in order to get a decent understanding of all aspects of carrier warfare one would be well advised to read Lundstrom. "THe First Team" and "The First Team and the Guadalcanal Campaign." There is a lot more to fighter ops as well as attack ops from carriers than there is in landbased ops. A lot of remarks made by our members show that they regard good characteristics of various AC the same for landbased as well as carrier based. Taint so! The BOB 109s I believe carried 60 rounds of 20MM per gun just like the Zeke. You seldom read that that was a weakness of the 109 but it was a definite weakness of the Zeke. Firing time for naval carrier fighters was highly important because fighters were scarce and the fighters had to make up for lack of numbers by being more able to stay in the fight. That is the reason why the guys who operated the carrier air groups did not like the British mandated gun arrangement of the F4F4 with six guns and much the less ammo of the F4F3.

I think you are correct in assering that 200m was the norm for engagement ranges, or even kill ranges. Hartmann was legendary in being able to take out an enemy at extremely long range.

I tend to disagree however, that the F4F armament was somehow superior to the A6M2s. The first thing to note about the Zeke, was that later marks increased the ammunition supply, however that asside, we need to compare the characteristics of the two weapons and their fitment to their repsective mounts

F4F-3 had 4 x 0.5 mg with an ammunition supply of 430 rpg. That gave them a a firing cycle of 34 seconds. However, the F4F-3 was a very limited production run. Far more common was the the F4F-4 which had 6 x 0.5 in MG, but rpg was reduced to 240 rounds. this gave a firing cycle of less than 20 seconds

The A6M had 2 x 20mm cannon, each with 60 rounds. The Type 99-1 20mm cannon had a rof of 520 rpm and a firing cycle of just 7 seconds. They were at a definitie disdavantage in terms of firing times, however this was compensated for by the fact that 20mm rounds had stopping power of more than 4 times that of the 50 cal. That in turn meant the usual burst of the 20mm battery was reduced to less than a second, whereas, for the 50 cal batteries the usual firing cycle is about 3-4 secs. So long as the Japanese pilots retained a higher skills base than their American counterparts, they were not disadvantaged too much by the armemnt they were carrying.

As far as range was concerned, in my opinion that is a function of muzzle velocity more than anything. Again the 50 cal had some advantage, but not greatly so. The MV of the F4s armament was rated at 2900 f/s according to my source, whereas the Type 99-1 had an Mv of 1970 f/s. Over a 300yd distance to target, the different flight times is 0.31 secs for the 50 cal, whilst the Type 99-1 ammo would take 0.45 secs. If usual combat speeds are assumed to be 240 mph, the respective targets will have moved 39 feet in that 0.3 secs, whilst the Type 99-1 would have allowed its target to move 59 feet. thats another 20 feet. How much of a difference would that make? Some, of course, but is it worth sacrificing firepower to the extent of having 1/4 the firepower per gun?

The other disadvantage that the F4F armament choice made was the weight of that armament. The f4F-3 had an all up armament + ammo weight of 512lbs. The F4F4 was carrying a weight of 420 lbs of armament + ammo weight. The Zero was carrying 176 lbs of armament + ammo (not inccluding the 7.7mm guns). This meant their armament was 34% that of the early marks Wildcat, and 42% that of the wing folding type. it was one of the reasons why the zero was so much more agile than the Wildcat, and why, IMO it was a superior mount.

Thorlifter said:

Didn't the La-9 have 4 nose mounted cannon's?


EDIT: Ahhhh, Tomo beat me to it.

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I think end of war versions of the La-7 had three nose mounted cannon. I guess the La-9 is disqulified by arriving post war, but I think at least some of them had four 23 mm cannon. Incidentaly, how much would synchronisation affect ROF?

Best air to air weapon, considering the ammunition, against 1-2 engined aircraft:
MG151/20 with Mine shell

Against heavy bombers:
R4M rocket

F4F3-285
F4F3A-65
FM1-839 (four guns)
FM2-4437 (four gun)
For a total of 5691 Wildcats with four guns The Wildcat was around 29 feet long. A 20 feet mistake in lead can make a big difference. The ballistics of the two 7.7s in the nose were different from the 20MMs both in flight time and trajectory. The IJN pilots did try to limit use of the cannon to relatively close range because of rainbow trajectory. In the Thach weave, the wing man of the target would often open fire at ranges well over 300 yards, knowing that he only faced the puny 7.7s early. IMO mixed armaments were not as efficient as homogeneous armaments.
There were 1169 F4F4s, a few with four guns.