FAA Seafire vs Corsair

EwenS · Jun 25, 2022

Looking at the USN carrier aircraft losses during Operation Torch for those 27 kills.

F4F-4 - Total available at start of operations - 109. Losses - 5 shot down & 20 operationally (Ranger - 4 shot down by Dewoitine 520 & Curtiss 75-A + 1 by ground fire, and 7 in other operational accidents from 54. Santee lost 10 were lost from her complement of 14 while Suwannee lost 3 from 29. Sangamon lost none from 12).
SBD-3 - Total available at start of operations - 36. Losses - 9
TBF-1 - Total available at start of operations - 27. Losses 10

Suwannee noted the light winds on D-Day causing her skipper, Jocko Clark, to seek areas of water ruffled by the breeze. She was recovering her aircraft with only 22 knots WOD (her own speed was max 18 knots). But that won't be an excuse for her 5 operational losses!

That was in 4 days of operations.

Wild_Bill_Kelso · Jun 25, 2022

Reluctant Poster said:
You seem to have a tenuous grasp on statistics. There are examples of people being shot in the head without suffering permanent damage, but it is not typical.

I did not post any statistics, I posted an example, in part because I thought this was fairly well known here.

You seem to have a tenuous grasp on analogies. And you are making some assumptions here.

Gunshot wounds to the head are indeed frequently fatal. Having worked in an emergency room, I'd say usually.

But does your analogy hold? I would say no, it does not. A better analogy might be "cannon strikes to the cockpit" in which case you might be right. But aircraft are large, strongly amde machines, protected by armor and other measures, and they don't always go down so easily.

So how about cannon strikes on fighters? Well, I can say "For a fact" that it is certainly not uncommon for a fighter to survive multiple 20mm cannon strikes. How do I know this? Because I have a particular interest in the operational histories of air to air engagements in various Theaters of WW2. Engagement with cannon armed Axis fighters (and bombers with defensive cannon) in the Pacific and Mediterranean happened almost every day in certain periods, and routinely resulted in damaged Allied fighters. Far more often than not, these actually returned to base in spite of that damage. I don't know what the precise ratio is but it's fairly high, around 3 or 4 to 1. Most of the Allied Aces in these Theaters were in fact involved in incidents, sometimes more than once, in which their aircraft were in fact struck multiple times and badly damaged, but they lived through it. Frequently there was photographic evidence, I only posted one example. Here is an example of the combat record:

July 11, 1942. British fighters from 73, 238, 2 SAAF and 5 SAAF squadrons engaged German fighters from JG 27 and 53, heavy fighters from 4.(H)/12 and bombers from II./LG 1. Losses for the British were 4 shot down and 8 damaged. (one Kittyhawk, two Tomahawk and one Hurricane shot down, one Kittyhawk three Tomahawks and three Hurricanes damaged but returned home, and one more Kittyhawk damaged ("single bullet in oil system") and force landed but later recoverd). German losses were 3 shot down and 1 damaged (two Bf 109F-4 "shot down by P-40s", one '60% damage', and one BF 110F-2 shot down.) The Bf 1094F-4 and Bf 110 are armed with 20mm cannon.

July 13, 1942 British fighters from 6, 601, 274, 450, 92, 1 SAAF, and 2 SAAF sqns engaged German fighters from JG 27 and 53, and Stukas from I and II./StG 3. Losses for the British were 2 shot down and 3 damaged (1 Kittyhawk badly damaged by flak, two Hurricanes shot down by Bf 109, two Hurricane IIc badly damaged by Bf 109). German losses were 2 shot down and 2 Stukas damaged (Bf 109F-4 "shot down by P-40" and pilot KiA, another "shot up in combat" and forced landed)

I'm not saying that this was always the ratio, but it certainly wasn't particularly unusual either.

We could assume of course, that all the damaged aircraft were only hit by light machine guns and all of the destroyed aircraft were hit by cannon, but I think that is highly unlikely.

My conclusion is that it was not actually so easy to tear an aircraft to pieces even with 20mm cannon. Conversely, with accurate aim, even a pair of light machine guns was sufficient to shoot down even pretty tough fighters, as the pilots of many Ki-43s demonstrated in China and the Pacific.

Reluctant Poster said:
Poon Lim survived 133 days drifting in the Atlantic on a life raft with no supplies but the vast majority of people adrift at sea don't last any near that time. Tsutomu Yamaguchi survived both Hiroshima and Nagasaki but thousands didn't. Outliers do not constitute the general trend.

I think this is another flawed analogy

Reluctant Poster said:
The statement that American fighter had very little trouble shooting down Axis fighters is pure nonsense. What is your basis for that statement?

You seem to be implying a bit more than I said, I was referring to cases where they hit the enemy fighter with their guns. We were discussing the power of the guns, specifically. I will extend this and note that British and American fighters had little trouble shooting down Axis bombers either.

Reluctant Poster said:
I learned in high school when someone says "I know for a fact" to discount what comes next.

Wild_Bill_Kelso · Jun 25, 2022

ThomasP said:
Hey Wild_Bill_Kelso,

re "Apparently some of the later Seafire marks that had the belt fed guns had ammunition left out to save weight."

What are your sources for this?

Here you go:

Armoured Aircraft Carriers

An overview of the production models of the Supermarine Seafire, its evolution and changing specifications.

www.armouredcarriers.com

Here is the direct quote:

"The Seafire LIII now had 200 more horsepower at 3000 feet than the Spitfire IX. Its fuselage was lighter by about 200 pounds. It was further lightened in 3 Wing by removing half the gun ammunition and taking away the two outboard .303s altogether. In this condition it could out-turn, out-roll and out-climb the Spitfire IX at all altitudes up to 10,000 feet, a feature which would come into urgent use on several occasions in the forthcoming operations. At last the Fleet Air Arm had an aircraft which could out perform, in a narrow heightband, its contemporary in the RAF."

ThomasP said:
re "You are overstating the case there. I know for a fact that numerous US and UK fighters operating in the Med and the Pacific survived multiple 20mm cannon strikes and flew home. The cannon shell explosion caused more damage but it was not going to automatically destroy a well built plane."

First, I never said that the 20mm "going to automatically destroy a well built plane". And you can apply the same rational to aircraft being hit by .50 cal, ie there were many (more) German and Japanese aircraft that made it home with multiple .50 cal hits.

What is your source that it was 'More'

ThomasP said:
Second, you seem to be of the opinion that what we are telling you about the effectiveness of the 20mm vs the .50 cal is our "opinion". This is not the case - what we are telling you is the opinion of the USN, the USAAF, the RAF, the RN/FAA, the Luftwaffe, the IJN, the IJA, the VVS, the Swiss, . . . . They ALL came to the same conclusion(s). (I think the Italians can be said to have thought the same way also, but I do not know enough about them to say for sure.)

You are extending 20mm is better than .50 cal, to "Two 20mm are better than six .50 cal." which was the statement I disagreed with in the video. I am not saying that 12.7mm = 20mm, though it would make the argument easier to win if I had.

Wild_Bill_Kelso · Jun 25, 2022

33k in the air said:
Depends on what one exactly means by "very little trouble."

If it is meant as saying the .50-cal was entirely sufficient for shooting down Axis fighters, then the statement is clearly true, because American fighters shot down plenty of Axis fighters during the war using only that caliber.

Indeed. 39 victories for the Seafire vs. 5000+ for the Hellcat says that pretty clearly.

33k in the air said:
Shooting down four-engine heavy bombers with only .50-cal weaponry is a different proposition, and not one American fighters really had to face.

Well, yeah. And I suspect if the Axis started fielding really tough four engined bombers, the US (and UK) would have up-gunned their fighters, since even 20mm cannon armed fighters had to be up-gunned by the Germans for example.

Wild_Bill_Kelso · Jun 25, 2022

EwenS said:
Looking at the USN carrier aircraft losses during Operation Torch for those 27 kills.

F4F-4 - Total available at start of operations - 109. Losses - 5 shot down & 20 operationally (Ranger - 4 shot down by Dewoitine 520 & Curtiss 75-A + 1 by ground fire, and 7 in other operational accidents from 54. Santee lost 10 were lost from her complement of 14 while Suwannee lost 3 from 29. Sangamon lost none from 12).
SBD-3 - Total available at start of operations - 36. Losses - 9
TBF-1 - Total available at start of operations - 27. Losses 10

Suwannee noted the light winds on D-Day causing her skipper, Jocko Clark, to seek areas of water ruffled by the breeze. She was recovering her aircraft with only 22 knots WOD (her own speed was max 18 knots). But that won't be an excuse for her 5 operational losses!

That was in 4 days of operations.

Still a great outing compared to how the Seafires did during the same campaign:

"Operation Torch also saw the Seafire begin to require its unenviable reputation as a fragile aircraft, suffering 40% losses during the campaign. Many of these losses were caused by poor visibility, but there was always an element of truth to this reputation, and the Merlin powered Seafires were not easy to land on carrier flight decks."

(and I don't think they made 27 claims either)

Not to mention the 70 aircraft lost to accidents at Salerno!

"The Seafire squadrons lost seventy aircraft in landing accidents, with most lost either when they hit the barrier after missing all of the arrestor wires, when the undercarriage failed, or when over-braking caused the Seafire to tip onto its nose. These accidents came over the course of a very large number of sorties. On 9 September the Seafires flew 265 sorties, losing 35 aircraft, but deterring around 40 German attacks. By the third day of the campaign there were only 39 of the original 100 Seafires left (many of the other aircraft were under repair). Even so on 11 September the Seafire pilots flew 160 sorties.

Although the overall figure for Seafire accidents was very high, with 42 written off, 32 of them in landing accidents, this figure was distorted by the difficult conditions on HMS Unicorn, which caused 21 of the landing accidents."

Supermarine Seafire: Development and Service Record

The Supermarine Seafire was the naval version of the Spitfire, but never shared that aircraft's impressive reputation, instead becoming known as a fragile aircraft not well suited to carrier operations

www.historyofwar.org

I'll grant you though that some of the problems seemed to be due to the CVE.

pbehn · Jun 25, 2022

Wild_Bill_Kelso said:
Conversely, aircraft like the Hellcat, Corsair, P-40, and P-51 which had the typical six .50 cal armament had very little trouble shooting down Axis fighters, particularly in the Pacific where most of the Naval combat was taking place. There is no getting around that six guns shoot more bullets than two guns.

Twelve guns shoot even more, The RAF decided on canon instead of 12 MGs because even 1940s bombers could take a staggering number of hits without going down. The P-40 and P-51 were uprated.

Wild_Bill_Kelso · Jun 25, 2022

pbehn said:
Twelve guns shoot even more, The RAF decided on canon instead of 12 MGs because even 1940s bombers could take a staggering number of hits without going down. The P-40 and P-51 were uprated.

Right but this is a little bit misleading, because you are talking about 12 light MGs, .303s to be precise. Let's look at that.

The .303 shoots an 11.3 gram bullet at 747 m/s. Rate of fire is 20 rps.

That works out to 3,060 joules per bullet. Multiply by 20 is 61,200. Multiply that by 12, it's 734,000. Still way below the six .50 cals (i.e. heavy MGs).

Six .50 browings = 1,328,351 Joules which is almost twice the energy of 12 x .303s. And it's more than the two 20mm.

We also know that the .303 has a shorter effective range, being lower velocity is less accurate, and has greatly inferior penetration against armor. The .50 gave the extra long range which is important particularly for hitting bombers (you need to outrange or at least equal the defensive guns)

The real reason the .303 was phased out as the main armament was that they had trouble against bombers with cannon or heavy MG as defensive armament.

ThomasP · Jun 25, 2022

Hey Wild_Bill_Kelso,

Thanks for the source re the Seafire sometimes having reduced ammo loads for performance purposes.

re 20mm vs .50 cal

Maybe I missed something, but I thought the main contention came from the statement that 1x 20mm was worth 2-3x .50 cal, a statement made by the USN operational research. Since all the major combatants came to the same ~conclusion, I do not see that there is any basis for the argument that the statement is not correct.

I realize that the energy output is greater for 6x .50 cal than for 2x 20mm IF YOU ARE FIRING SOLID PROJECTILES and talking only of kinetic energy, but if you add in the equivalent chemical energy supplied by the explosive content of the 20mm HE projectile, then using your math we get:

six 12.7mm Browning = 78 rounds per second, at 43 grams, a 'weight' of 3,354 grams, or 3+ kg at 890 m/s = KE of 1,328,351.7 Joules

two 20mm Hispano II = 20 rounds per second, at 122 grams, a 'weight' of 2,440 grams, or 2+ kg at 860 m/s = KE of 902,312 Joules + CE of 20 x 8 x 4180 = 902,312 + 668,800 = 1,571,112 Joules

NOTE that I subtracted 8 grams from each 20mm projectile in terms of kinetic energy and added 8 grams of TNT equivalent chemical energy at 4180 Joules/gram TNT.

Wild_Bill_Kelso · Jun 25, 2022

ThomasP said:
Hey Wild_Bill_Kelso,

Thanks for the source re the Seafire sometimes having reduced ammo loads for performance purposes.

re 20mm vs .50 cal

Maybe I missed something, but I thought the main contention came from the statement that 1x 20mm was worth 2-3x .50 cal, a statement made by the USN operational research. Since all the major combatants came to the same ~conclusion, I do not see that there is any basis for the argument that the statement is not correct.

I realize that the energy output is greater for 6x .50 cal than for 2x 20mm IF YOU ARE FIRING SOLID PROJECTILES and talking only of kinetic energy, but if you add in the equivalent chemical energy supplied by the explosive content of the 20mm HE projectile, then using your math we get:

six 12.7mm Browning = 78 rounds per second, at 43 grams, a 'weight' of 3,354 grams, or 3+ kg at 890 m/s = KE of 1,328,351.7 Joules

two 20mm Hispano II = 20 rounds per second, at 122 grams, a 'weight' of 2,440 grams, or 2+ kg at 860 m/s = KE of 902,312 Joules + 20 x 8 x 4180 = 902,312 + 668,800 = 1,571,112 Joules

NOTE that I subtracted 8 grams from each 20mm projectile in terms of kinetic energy and added 8 grams of TNT equivalent chemical energy at 4180 Joules/gram TNT.

I don't think it actually works that way (stacking the chemical energy on top of the joules) though I am not a physicist.

The .50 cal API ammunition I mentioned also has 2% of incendiary which does have some additional effect.

"Worth two to three" .50 cal (if I'm reading your post correctly) is not the same as "is better than the armament of a Hellcat" (i.e. one Hispano 20mm is better than three .50 Brownings) which is the claim made in the video that I objected to. A pair of 20mm Hispano may be equivalent to two .50 cals, I do not believe that two 20mm are more effective than six .50.

pbehn · Jun 25, 2022

Wild_Bill_Kelso said:
Right but this is a little bit misleading, because you are talking about 12 light MGs, .303s to be precise. Let's look at that.

The .303 shoots an 11.3 gram bullet at 747 m/s. Rate of fire is 20 rps.

That works out to 3,060 joules per bullet. Multiply by 20 is 61,200. Multiply that by 12, it's 734,000. Still way below the six .50 cals (i.e. heavy MGs).

Six .50 browings = 1,328,351 Joules which is almost twice the energy of 12 x .303s. And it's more than the two 20mm.

We also know that the .303 has a shorter effective range, being lower velocity is less accurate, and has greatly inferior penetration against armor. The .50 gave the extra long range which is important particularly for hitting bombers (you need to outrange or at least equal the defensive guns)

The real reason the .303 was phased out as the main armament was that they had trouble against bombers with cannon or heavy MG as defensive armament.

The basic argument is the same, adding up the energy is one way to look at it, but with rifle MG fire it could make dozens of holes in a propeller and leave a still functioning propeller. When the RAF switched to canon the 0.5 wasnt particularly reliable or rapid firing.

Wild_Bill_Kelso · Jun 25, 2022

I wouldn't say cannon is bad. In fact, so long as you have a reasonable ammunition supply, I'd say four Hispano 20mm is definitely better than six .50 Brownings. Maybe better than eight.

And as we know, the US didn't adapt the 20mm mainly because they couldn't figure out how to make them work properly. I still don't quite understand that one.

The .50 cal wasn't a perfect fighter weapon, by any means, but they had made them more efficient (faster shooting, lighter, more reliable) by the later part of the war. And there are some advantages to having the multiple heavy machine guns.

The British were also using .50 cal guns on many aircraft, more or less replacing the .303s, later in the war. As you note, by then they were more reliable.

Today the 20mm is king, the only rival are mainly 30mm.

MikeMeech · Jun 25, 2022

Hi

For information, some comments on the use of 20mm Hispano guns during 1941 from 'The Guns of the Royal Air Force 1939-1945' by G F Wallace:

Mike

Wild_Bill_Kelso · Jun 25, 2022

No doubt, the improvement from .303s to 20mm was a major leap forward in firepower. But enemy aircraft also disintegrated under the concentrated burst of .50 cals too.

Here is an interview with Alexander Vraciu

He's describing the famous mission where, flying his F6F-3 Hellcat, he destroyed six Japanese dive bombers on a single sortie. At least two of them literally exploded.

Direct quote: "There was one on the way to there, I got him. Boy he blew up in all kinds of pieces."

Nor was this a fluke. He found his aircraft, and it's armament, sufficient to destroy multiple enemy aircraft several times:

On January 29 1944, he claimed 3 x G4M "Betty"
On February 16, 1944, he claimed 3 x A6M and 1 x "Rufe" (A6M2-N)
On April 29, 1944, he claimed 2 x A6M
And on June 20, he got his 6 x D4Y "Judy" dive bombers.

No doubt he was an extraordinarily capable pilot. But I think that is evidence that the firepower was more than adequate.

Shortround6 · Jun 25, 2022

Wild_Bill_Kelso said:
We also know that the .303 has a shorter effective range, being lower velocity is less accurate, and has greatly inferior penetration against armor. The .50 gave the extra long range which is important particularly for hitting bombers (you need to outrange or at least equal the defensive guns)

This gets trotted all the time but it is pretty much crap, despite what many veterans think.
You also have to compare time lines. British .50 cal ammo in 1940/41 had just about the same veleocity as .303 ammo. The high velocity stuff (over 2800fps) doesn't even show up in the US until late 1940 and sure doesn't replace existing US ammo until later.
The US .50 had a few problems with practical results verses theory. The US .50 performed rather well against test plates in tests. However the long pointy nose, which helped retain veleocity also meant it was more likely to yaw sideways when going through aircraft skin/light structure and hit the armor plate sideways. It worked, kind of, but performance of single rounds (or small groups) was erratic.

Just about any aircraft gun in WW II was limited in range by the sighting equipment and the need to lead moving aircraft. These two factors were much more important than trajectory.
The .50 needed a bit less lead than just about anything else but by the time is gets significant you are out past 300yds. If this longer range stuff was really effective the P-38 should have been shooting down all kinds of stuff at 600yds or beyond. No cross over and the guns were never off by more that 22inches from the sight out or 600yds (or beyond) On planes with wing mounted guns if you were close enough to get good hits with a .50 you were within effective range of the defensive guns.

Wild_Bill_Kelso said:
The .50 cal API ammunition I mentioned also has 2% of incendiary which does have some additional effect.

Yes, no, maybe.
1. the M8 API didn't show up until 1943. It did take over as the standard cartridge as supplies allowed.
2. The incendiary compound was in the nose of the projectile ahead of the AP core. Which means that incendiary compound rarely made past the armor or heavy structure. The bullet jacket and the IC was get stripped away as the core penetrated. The Russians used a very similar projectile in their 12.7mm guns (and this may be where the US got it).

The US incendiary MI didn't show up until 1941? (sorry all .50cal in the BoB fans) and apparently wasn't very good. The British didn't like it and worked on their own. The US went to the M8 instead of continuing on with the M1.
The M23 Incendiary was used in operational trials in 1944/45 but had problems (like igniting in the gun barrels or just in front of the guns. ) It was sorted out by Korea but it took several production shut downs and two changes of factory suppling the ammo to finally get acceptable quality.

Please note that the 2% payload of the .50 cal M8 was just under twice the payload of a .303 incendiary bullet and the late 1942/43 Spitfire with four .303s had two guns loaded with AP ammo and two guns with incendiary.

One 20mm shell with 10 grams of incendiary held more than 12 rounds of .50 cal M8 API. By part way through the war the British were just screwing a hardened nose cap on the shell body with the incendiary inside. The shell body was going act like an AP or semi AP round, pierce the armor or heavy structure and breakup as it penetrated scattering the IC inside the aircraft into the area the armor plate was supposed to be protecting.

Things changed with the ammo of various guns as the war progressed and blanket statements often confuse things.

Please that that the US army wanted 20mm guns in P-70 nightfighters and the P-61 nightfighters. Some of the Navy single seat night fighters got 20mm guns.

Also please note the times of flight and trajectory of the 20mm Hispano gun and .50 cal are nearly identical until you get past 600yds and very, very , very few pilots had any business firing at targets over 600yds away. Other 20mm gun performance can vary considerably.

pbehn · Jun 25, 2022

Shortround6 said:
This gets trotted all the time but it is pretty much crap, despite what many veterans think.
You also have to compare time lines. British .50 cal ammo in 1940/41 had just about the same veleocity as .303 ammo. The high velocity stuff (over 2800fps) doesn't even show up in the US until late 1940 and sure doesn't replace existing US ammo until later.
The US .50 had a few problems with practical results verses theory. The US .50 performed rather well against test plates in tests. However the long pointy nose, which helped retain veleocity also meant it was more likely to yaw sideways when going through aircraft skin/light structure and hit the armor plate sideways. It worked, kind of, but performance of single rounds (or small groups) was erratic.

Just about any aircraft gun in WW II was limited in range by the sighting equipment and the need to lead moving aircraft. These two factors were much more important than trajectory.
The .50 needed a bit less lead than just about anything else but by the time is gets significant you are out past 300yds. If this longer range stuff was really effective the P-38 should have been shooting down all kinds of stuff at 600yds or beyond. No cross over and the guns were never off by more that 22inches from the sight out or 600yds (or beyond) On planes with wing mounted guns if you were close enough to get good hits with a .50 you were within effective range of the defensive guns.

Yes, no, maybe.
1. the M8 API didn't show up until 1943. It did take over as the standard cartridge as supplies allowed.
2. The incendiary compound was in the nose of the projectile ahead of the AP core. Which means that incendiary compound rarely made past the armor or heavy structure. The bullet jacket and the IC was get stripped away as the core penetrated. The Russians used a very similar projectile in their 12.7mm guns (and this may be where the US got it).

View attachment 675096

The US incendiary MI didn't show up until 1941? (sorry all .50cal in the BoB fans) and apparently wasn't very good. The British didn't like it and worked on their own. The US went to the M8 instead of continuing on with the M1.
The M23 Incendiary was used in operational trials in 1944/45 but had problems (like igniting in the gun barrels or just in front of the guns. ) It was sorted out by Korea but it took several production shut downs and two changes of factory suppling the ammo to finally get acceptable quality.

Please note that the 2% payload of the .50 cal M8 was just under twice the payload of a .303 incendiary bullet and the late 1942/43 Spitfire with four .303s had two guns loaded with AP ammo and two guns with incendiary.

One 20mm shell with 10 grams of incendiary held more than 12 rounds of .50 cal M8 API. By part way through the war the British were just screwing a hardened nose cap on the shell body with the incendiary inside. The shell body was going act like an AP or semi AP round, pierce the armor or heavy structure and breakup as it penetrated scattering the IC inside the aircraft into the area the armor plate was supposed to be protecting.

Things changed with the ammo of various guns as the war progressed and blanket statements often confuse things.

Please that that the US army wanted 20mm guns in P-70 nightfighters and the P-61 nightfighters. Some of the Navy single seat night fighters got 20mm guns.

Also please note the times of flight and trajectory of the 20mm Hispano gun and .50 cal are nearly identical until you get past 600yds and very, very , very few pilots had any business firing at targets over 600yds away. Other 20mm gun performance can vary considerably.

There is another side to the discussion that isnt pure science. The British were not happy with rifle calibre guns in the BoB, but their knowledge of losses was limited to what was shot down and landed in South England. They were not aware of how many bombers ditched, made forced landings in France or landed with severe damage and dead or injured crew. Similarly on the Schweinfurt Regensburg raid on 17 August 60 B-17s were shot down but 50 to 95 were badly damaged, many of those who landed in North Africa didnt fly again. In my opinion developing weapons that could take down a B-17 in a single hit or pass may not have been the best policy, if it makes the attacker more vulnerable.

Wild_Bill_Kelso · Jun 25, 2022

Shortround6 said:
This gets trotted all the time but it is pretty much crap, despite what many veterans think.

I trust the Veterans. I hope you can forgive me.

Shortround6 said:
You also have to compare time lines. British .50 cal ammo in 1940/41 had just about the same veleocity as .303 ammo. The high velocity stuff (over 2800fps) doesn't even show up in the US until late 1940 and sure doesn't replace existing US ammo until later.

We were talking about Seafire vs. F4U Corsair (see the thread title) so 1940/41 isn't very relevant is it? I'm sure the British had their reasons for sticking with the .303 and then jumping strait to the 20mm Hispano instead of using HMG (how could they resist trying out those excellent Hispano-Suiza designs, like so many other nations around the world!), though as I noted, they did start using .50 Brownings in some of their fighters later in the war. Not that it's big news.

Shortround6 said:
The US .50 had a few problems with practical results verses theory. The US .50 performed rather well against test plates in tests. However the long pointy nose, which helped retain veleocity also meant it was more likely to yaw sideways when going through aircraft skin/light structure and hit the armor plate sideways. It worked, kind of, but performance of single rounds (or small groups) was erratic.

Just about any aircraft gun in WW II was limited in range by the sighting equipment and the need to lead moving aircraft. These two factors were much more important than trajectory.
The .50 needed a bit less lead than just about anything else but by the time is gets significant you are out past 300yds. If this longer range stuff was really effective the P-38 should have been shooting down all kinds of stuff at 600yds or beyond. No cross over and the guns were never off by more that 22inches from the sight out or 600yds (or beyond) On planes with wing mounted guns if you were close enough to get good hits with a .50 you were within effective range of the defensive guns.

When attacking a maneuvering fighter, 300 meters was quite long range. Quite often fighter pilots didn't open fire until they were within 200 meters, some like the Soviets liked to wait until they were within 100 meters. But there are two cases where longer shots could be and were tried, and not infrequently, with success:

During a long slow approach to a bomber (not the ideal way to attack bombers but this was sometimes how it was done, for a variety of reasons)
During a long chase of a fighter which is a little bit faster and is trying to run away

In these circumstances, US fighter pilots, and British pilots flying US made aircraft did in fact score some extraordinarily long range victories. Even with some unexpected snap-shots on a few occasions. Many of these incidents are well documented. I think the typical Veteran is correct in their fear of approaching a bomber that has a 20mm (or 13mm or 12.7mm) defensive gun if they are only armed with .303s. The .50 cal or 20mm will not only score hits from further away, they will also more quickly disable defensive guns and gunners.

Shortround6 said:
Yes, no, maybe.

The US incendiary MI didn't show up until 1941? (sorry all .50cal in the BoB fans) and apparently wasn't very good. The British didn't like it and worked on their own. The US went to the M8 instead of continuing on with the M1.

Again, by the time you are talking about Hellcats, Corsairs, and Seafires, which we were, the M8 round is there. I never said anything about using .50 cal in the BoB.

Shortround6 said:
The M23 Incendiary was used in operational trials in 1944/45 but had problems (like igniting in the gun barrels or just in front of the guns. ) It was sorted out by Korea but it took several production shut downs and two changes of factory suppling the ammo to finally get acceptable quality.

Please note that the 2% payload of the .50 cal M8 was just under twice the payload of a .303 incendiary bullet and the late 1942/43 Spitfire with four .303s had two guns loaded with AP ammo and two guns with incendiary.

One 20mm shell with 10 grams of incendiary held more than 12 rounds of .50 cal M8 API. By part way through the war the British were just screwing a hardened nose cap on the shell body with the incendiary inside. The shell body was going act like an AP or semi AP round, pierce the armor or heavy structure and breakup as it penetrated scattering the IC inside the aircraft into the area the armor plate was supposed to be protecting.

That's a good innovation. But multiple bullets striking tended to peel away layers of fuselage or wing pretty quickly, exposing fuel to the flashes of the rest of the oncoming bullets. That's one of the advantages of shooting 80 rounds per second instead of 20. And 12.7mm penetrated armor well.

The M8 incendiary on the .50 Browning wasn't actually made for starting fires, it was made for marking targets so the pilot could see if he was getting hits. It turned out to have the happy coincidental / side effect of starting fires on the enemy aircraft as fumes from punctured fuel tanks or hydraulic lines ignited. But it did indeed work pretty well which is why they widely adopted it.

Shortround6 said:
Things changed with the ammo of various guns as the war progressed and blanket statements often confuse things.

Please that that the US army wanted 20mm guns in P-70 nightfighters and the P-61 nightfighters. Some of the Navy single seat night fighters got 20mm guns.

Also please note the times of flight and trajectory of the 20mm Hispano gun and .50 cal are nearly identical until you get past 600yds and very, very , very few pilots had any business firing at targets over 600yds away. Other 20mm gun performance can vary considerably.

I already pointed out that the US wanted to use 20mm, they had an unusual degree of difficulty to get them working (again for reasons I still don't fully understand). I guess some places were better at borrowing some of these excellent Franco / Spanish / Swiss design concepts than others.

eagledad · Jun 25, 2022

Gentlemen,

IMHO the following link gives a balanced account of the effectiveness of WW 2 aircraft armament

WORLD WAR 2 FIGHTER GUN EFFECTIVENESS

Eagledad

Shortround6 · Jun 25, 2022

Wild_Bill_Kelso said:
I trust the Veterans. I hope you can forgive me.

Nope.
How many veterans that flew P-38s in fall of 1943 and early 144 would tell you that you were supposed to cruise a P-38 at high rpm and low boost?
A lot of those men were not gunnery experts, they were repeating what they had been told.
Or listed to some veterans talk about the .45 automatic pistol and how inaccurate it was.

Wild_Bill_Kelso said:
We were talking about Seafire vs. F4U Corsair (see the thread title) so 1940/41 isn't very relevant is it? I'm sure the British had their reasons for sticking with the .303 and then jumping strait to the 20mm Hispano instead of using HMG (how could they resist trying out those excellent Hispano-Suiza designs, like so many other nations around the world!), though as I noted, they did start using .50 Brownings in some of their fighters later in the war. Not that it's big news.

Wild_Bill_Kelso said:
We also know that the .303 has a shorter effective range, being lower velocity is less accurate, and has greatly inferior penetration against armor. The .50 gave the extra long range which is important particularly for hitting bombers (you need to outrange or at least equal the defensive guns)

The real reason the .303 was phased out as the main armament was that they had trouble against bombers with cannon or heavy MG as defensive armament.

The British had very good reasons for skipping the .50 cal until late in the war, and some of the those reasons go back to before WW II started and carried through until 1942-43. But you want to ignore those reasons?
One of the reasons was that they didn't have the money/production facilities for both the 20mm cannon and the .50 cal guns. When they started putting .50 cal guns into Spitfires they were getting the guns and ammo lend-lease. No British gun factory, no British workers, a fair amount of the ammo from American factories. Makes the choice a whole lot easier.
British broke ground for the 20mm gun factory in 1938.

Now since the British were phasing out the .303 in the fall of 1940/spring of 1941 and sense most of their experience at that time was due to the BoB I am not sure why you are so quick to bypass the BoB, since that is the basis for your argument against it.

However also note that the British fighters in the BoB did not have the best ammo selection going. Out of the eight guns 3 were often loaded with ball (lead core) ammunition. Sometimes only one gun had the Dixon incendiary and two had the older incendiary tracer ( which burned up much of it's incendiary charge on the flight to the target. and two had AP ammo. The Dixon (De Wilde) ammo in tests showed it was twice as effective at setting fire to aircraft fuel tanks as the older Buckingham ammunition.
British proof tests for the .303 AP called for 70% of the bullets to penetrate 10mm of armor at 100yds.
If the British had the production capacity for a lot more Dixon/De Wilde ammo and more AP they might have been happier with the .303 guns. There would have been fewer German bombers going home with several hundred hits.

Wild_Bill_Kelso said:
That's a good innovation. But multiple bullets striking tended to peel away layers of fuselage or wing pretty quickly, exposing fuel to the flashes of the rest of the oncoming bullets. That's one of the advantages of shooting 80 rounds per second instead of 20. And 12.7mm penetrated armor well.

20mm doesn't have to peel away layers, not that there were much in way of layers to begin with. A 20mm is either going to punch through the thin parts and out the other side or it is going to go deep inside and do a lot of damage without having have other rounds open things up for it.

Wild_Bill_Kelso said:
This guy's 79th FG P-40 was hit with six 20mm cannon shells and made it back, including 3 in the wings (where there is a fuel tank) and one right behind the armor plate where he was sitting (where there is another fuel tank).

Not all 20mm shells were created equal and and not all fuses were created equal.
Now as you well know the fuel tanks in the P-40s wing were pretty much under the cockpit and the pilot in the photo is standing on empty space. I don't have any other photos so I don't know if the 3 shells that hit the wing went up the belly where the fuel tanks were or hit outside the wheel wells a number of feet away from the tanks.
Germans used two different 20mm shells in the MG 151/20 gun. The famous mine shell with 20 G of explosive filler but not much metal and the HET round that held about 3.7G of HE. (the tracer took up some space). A 20mm Hispano HE round held 10.2-10.5 grams of HE.
The Round in the photo looks like it exploded just about where the fuselage skin was, Not against the armor plate behind the pilot. Both the German and the British had a lot of trouble with bad fuses, both number of duds and the with shells exploding too soon and not inside the aircraft. Things got better latter but not perfect.
As far as kinetic energy goes, the MG 151/20 had about 62% of the energy that the Hispano had.

Let's try to compare apples to apples.

PAT303 · Jun 26, 2022

Shortround6 said:
This gets trotted all the time but it is pretty much crap, despite what many veterans think.
You also have to compare time lines. British .50 cal ammo in 1940/41 had just about the same veleocity as .303 ammo. The high velocity stuff (over 2800fps) doesn't even show up in the US until late 1940 and sure doesn't replace existing US ammo until later.
The US .50 had a few problems with practical results verses theory. The US .50 performed rather well against test plates in tests. However the long pointy nose, which helped retain veleocity also meant it was more likely to yaw sideways when going through aircraft skin/light structure and hit the armor plate sideways. It worked, kind of, but performance of single rounds (or small groups) was erratic.

I've posted this before and was shouted down, the .50 AP does penetrate well "IF" it hits a plate set at 90 degree's unobstructed, unfortunately that's not realistic, the bullet has to first penetrate the fuselage or wing structure which are all oblique angles and this is where the long pointed nose of the .50 is a disadvantage, it's easy tipped off it's axis causing it to keyhole resulting in a total loss of penetrating power. Another thing has to be said, it took a very long time for both the 20mm and .50 cal to be reliable, both the guns and ammunition, the .50 cal didn't have reliable API or HE ammunition until after the 20mm and well after the .303, the first specialisted aircraft specific incendiary .50 BMG rounds were upscaled De Wilde projectiles.

PAT303 · Jun 26, 2022

Shortround6 said:
The British had very good reasons for skipping the .50 cal until late in the war, and some of the those reasons go back to before WW II started and carried through until 1942-43. But you want to ignore those reasons?

Lets not forget weight, the .50 is a heavy gun and so is it's ammo, until two speed, two speed/two stage engines became the norm weight was a major issue for fighters, that's why the Spit only had 85G of fuel.

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