50 cal vs rail stock

[Rjel]

All I can say is wow. I've never had a chance to fire a .50 cal but I would love to. If this round can hole heavy rail stock like this, an engine block shouldn't have been any tougher to penetrate in most places. As to any seat armor in R/L 109s or 190s, I can't see those having been any more durable. 

 

I like the .50s we have in the sim in their current incarnation. It took a few weeks for the new dispersion patterns to feel right for me but now I'm pretty pleased. Once we get APIs, you'll not pry me away from any U.S.A.A.F fighters. IF we ever do get to go to the P.T.O, they'll be absolutely devastating against Japanese A/C, as they obviously were in real life. 

 

If the mods feel this post should be moved, feel free.

[grcurmudgeon]

I had some fun starting a P-40 campaign in Moscow with PWCG. The 6 .50-cals were REALLY nice. Have to figure out the engine, but the firepower was SWEET.

[PatrickAWlson]

Somethings to consider.

1. He is firing a modern rifle.  No idea what the relative muzzle velocity of his gun vs. a 1940s Browning is.  Browning did have a high muzzle velocity though.

2. He is firing from dead on.  Most of the time a bullet striking a heavy piece of metal on a plane will strike at an angle, diminishing penetration or causing a deflection.

 

The Browning .50 could definitely penetrate an armored seat or an engine block.  The US shot down a heck of a lot of planes with it, and without the need to fight a heavy bomber, it was very much fit for purpose.  It's just not the case that it always would.  Firing from 5-7 at convergence would cause serious harm.

[JtD]

That part of the rail is pretty soft steel, armour grade steel is easily twice as tough. The only hard steel of a rail is on the running surface (i.e. on the top) and that had been taken off. In other words, you've got a more powerful round vs. a less strong metal. It's not at all representative for a WW2 0.50 vs. an armour plate.

 

Still pretty impressive and yes, not looking good for engine blocks and such.

[Rjel]

2 minutes ago, PatrickAWlson said:

Somethings to consider.

1. He is firing a modern rifle.  No idea what the relative muzzle velocity of his gun vs. a 1940s Browning is.  Browning did have a high muzzle velocity though.

2. He is firing from dead on.  Most of the time a bullet striking a heavy piece of metal on a plane will strike at an angle, diminishing penetration or causing a deflection.

 

The Browning .50 could definitely penetrate an armored seat or an engine block.  The US shot down a heck of a lot of planes with it, and without the need to fight a heavy bomber, it was very much fit for purpose.  It's just not the case that it always would.  Firing from 5-7 at convergence would cause serious harm.

Interesting points to be sure. For all the same reasons, I always think the same thing when the Youtube video is trotted out here showing the 30mm cannon ripping up a Spitfire fuselage from nearly point blank range as proof it under performs in this sim.

 

4 minutes ago, JtD said:

That part of the rail is pretty soft steel, armour grade steel is easily twice as tough. The only hard steel of a rail is on the running surface (i.e. on the top) and that had been taken off. In other words, you've got a more powerful round vs. a less strong metal. It's not at all representative for a WW2 0.50 vs. an armour plate.

 

Still pretty impressive and yes, not looking good for engine blocks and such.

Good points too.

[the_emperor]

29 minutes ago, Rjel said:

I always think the same thing when the Youtube video is trotted out here showing the 30mm cannon ripping up a Spitfire fuselage from nearly point blank range as proof it under performs in this sim.

 

One has to keep in mind though, that the German HE Mineshells are of different design and rely on blast effect which is further increased by a delay charge to let the shell go off inside the highly stressed airframe. Kinetic energy/mass/velocity dont play a big role in the design of the shell as a means to deliver damage and it does not have any big AP perfomance.

But if you think the .50 is a good AP perfomer the 20mm Hispano/M3 fires a solid 0.29lbs(131g) slug at 2,730feet/s (832m/s). this wil probably go through a 109 back to front like a hot knife through warm butter.

[Jaws2002]

1 hour ago, PatrickAWlson said:

Somethings to consider.

1. He is firing a modern rifle.  No idea what the relative muzzle velocity of his gun vs. a 1940s Browning is.  Browning did have a high muzzle velocity though.

2. He is firing from dead on.  Most of the time a bullet striking a heavy piece of metal on a plane will strike at an angle, diminishing penetration or causing a deflection.

 

The Browning .50 could definitely penetrate an armored seat or an engine block.  The US shot down a heck of a lot of planes with it, and without the need to fight a heavy bomber, it was very much fit for purpose.  It's just not the case that it always would.  Firing from 5-7 at convergence would cause serious harm.

 

One more thing to consider.  Anything that the bullet has to pass through, before it hits the armor, will destabilize/deform the round and  significantly reduce it's penetration. A tumbling .50cal round is still very dangerous, but it may not penetrate the armor.

 

[357th_KW]

2 hours ago, PatrickAWlson said:

Somethings to consider.

1. He is firing a modern rifle.  No idea what the relative muzzle velocity of his gun vs. a 1940s Browning is.  Browning did have a high muzzle velocity though.

 

 

That Serbu BFG50A has a 26" barrel - an AN/M2 has a 36" barrel so muzzle velocity is likely far lower then from an aircraft gun.

[oc2209]

On 2/2/2022 at 12:50 PM, Rjel said:

Interesting points to be sure. For all the same reasons, I always think the same thing when the Youtube video is trotted out here showing the 30mm cannon ripping up a Spitfire fuselage from nearly point blank range as proof it under performs in this sim.

 

Yeah, no.

 

Functionally there's no difference between a 30mm HE hitting something at 20m or 200m. Why? Because if that were the case, then AA (ground based) cannon fire would be ineffectual. AA is typically fired from greater distances than the average aerial engagement.

 

Spoiler

 

 

Once again, I managed to get 5 hits on a P-51 without catastrophic structural failure or explosion. This takes no effort on my part. It was one of two quicks against a P-51 I just flew an hour ago.

 

The pilot died from the second near-cockpit port wing hit. That's the only hit that really mattered. Not the starboard near-aileron hit (note that the aileron was still functional), not the tail hit, not the spine hit, and not the first hit in the same location.

 

If it were a B-17 instead of a P-51, I'd say whatever, there's no guarantee a bomber must be shot down with 5x30mm hits. It's just likely to be shot down by that many hits. However, a fighter is a totally different ballgame. I'd say 3x30mm hits is extreme in the annals of improbability. And 5x30mm only succeeding by causing pilot death on the fifth is kinda sad. 

 

For the record, the Russian 37mm HE can also hilariously underperform, so this isn't just a Luftwhining issue.

Edited February 5, 2022 by oc2209

[Mtnbiker1998]

I just love seeing the mental gymnastics that go on in threads like these, acting as if "WeLl ThIs Is A ShOrT rAnGe ShOt," like 500 meters is such a long range for a ~700gr projectile going ~3000fps, like the Army doesn't use this bullet as an Anti Material round out to 2000 meters. This ain't your grandaddy's .223 hunting rifle.
 

I also love hearing people talk about how "Well the bullet has to penetrate through the entire airframe!" and how that will cause the bullet to tumble and deform, at least until the conversation turns to aerodynamic damage, where the data shifts to "Well the round is just punching through Aluminum, so it won't deform or tumble or anything!! "ClEaN HoLeS nO dRaG!!"

 

Its almost like people don't know what they're talking about and will just spout whatever nonsense they want when its convenient to making .50s as inneffective as possible.

In the meantime I'm having a blast punching through armor and killing pilots in my Mustang. Stay mad Luftwhiners ✌️

Edited February 3, 2022 by Mtnbiker1998

[354thFG_Panda_]

Locked in 3...2...

[Yogiflight]

Doesn't really have to do with it, but I thought it might be interesting to watch

Very sad, he didn't hit with the thungsten round. Would have been very interesting to see if it penetrated

[MasterBaiter]

Here we go again

[Jaws2002]

11 hours ago, Mtnbiker1998 said:

~700gr projectile going ~3000M/s,

 

Are you sure about that? go do more digging, because you failed miserably. 

 

11 hours ago, Mtnbiker1998 said:

This ain't your grandaddy's .223 hunting rifle.

 

 My granddaddy didn't hunt with .223, because it wasn't even invented back then  and most of today's .50 cal is not the same thing they were shooting back in ww2.

 The vast majority of WW2 ammunition was  replaced with newer, more performant loads. In most cases the new loads are faster and hit their intended velocity from much shorter barrels. New powers, new metallurgy, new bullet construction...

      

 

 

11 hours ago, Mtnbiker1998 said:

I also love hearing people talk about how "Well the bullet has to penetrate through the entire airframe!" and how that will cause the bullet to tumble and deform,

 

 

There's stuff behind the pilot in most planes, you know. I had a ww2 test somewhere, exactly about the penetration behind aluminum sheet, but I didn't find it.

I did find this report that is relevant to the discussion. 

 

 

See that? If there's fuel in the tank and the fuel level is above the hit point, .50 cal AP can't get to the pilot at 200 yards! 

 

 

 

Edited February 3, 2022 by Jaws2002

[6./ZG26_Custard]

14 minutes ago, Jaws2002 said:

There's stuff behind the pilot in most planes, you know

One interesting statistic specifically from the point of view of US  bomber crews was that 70% of the causalities were caused by shattered pieces of aircraft structure they were flying in, according to the National museum of the US Air Force.

I find that surprising when considering that parts of a bomber are unarmoured with room for a round to travel in.

All ammunition, irrelevant of which side is firing it seems to be effected little by objects in their flight path. Hitting spars, fuel tanks, rear gunners, fuselage supports and armour doesn't seem to matter as much as it should. Added to this, there is little to no effect to some aerodynamic properties. Hopefully as the developers have hinted, they will investigate damage modelling etc, when time allows.  

[Jaws2002]

23 minutes ago, 6./ZG26_Custard said:

One interesting statistic specifically from the point of view of US  bomber crews was that 70% of the causalities were caused by shattered pieces of aircraft structure they were flying in, according to the National museum of the US Air Force.

 

I was only talking about armor penetration.  A heavy, tumbling bullet will still cause a lot of damage, spall and shrapnel, but it's ability to penetrate armor, after it hit something else,  will be drastically reduced.

 Look at how those thin standoff skirts worked on Panther. They destabilize and deformed the 14.5mm bullet just enough, to  prevent it from penetrating the thin side armor. 

 

Edited February 3, 2022 by Jaws2002

[[CPT]Crunch]

Might work on the first bullet, but the rapidly following next 20 not so much.

[Eisenfaustus]

36 minutes ago, [CPT]Crunch said:

Might work on the first bullet, but the rapidly following next 20 not so much.

They don’t go all through the same hole. Not on the ground and Especially not in s WWII aerial dogfight. 

[Mtnbiker1998]

2 hours ago, Jaws2002 said:

 

go do more digging

Many different varieties of modern .50 BMG out of long barrels can hit that. go look it up yourself. far from the "LoL ePiC fAiL" you were hoping for there bud. So the velocity of an aircraft M2 firing ww2 loads might be slightly different, its frankly nitpicking (the wrong numbers sure seemed ok for the devs for how long?) Its a very heavy bullet going very, very fast and it retains that energy very well. Thats literally the whole point of the round. sue me. At least I googled, more than the average idiot here can say.

 

2 hours ago, Jaws2002 said:

See that? If there's fuel in the tank and the fuel level is above the hit point, .50 cal AP can't get to the pilot at 200 yards! 

 

 

 

Ignoring the fact that you're conveniently ignoring the 2nd half of my point (Which actually even further proves said point, forumgoers love flipping narratives whenever it makes .50s perform worse)

 

Gee, yknow I'm not great at math, and I guess my reading comprehension isn't as perfect as yours, but it almost, almost looks like 30% of the bullets did in fact penetrate the armor at 200 yards. with 6 .50 cals firing, thats still a lot of bullets considering one .50 cal slug is still plenty to incapacitate a pilot or an engine. Thats still one dead kraut, and still the expected amount of neural backflips from the likes of you.

 

Also an interesting note from your data point, is that the pilots armor is only 8-11mm thick, significantly thinner than those rails, harder steel or not. Saying nothing of course, of late war Germany's impeccable quality of metallurgy cough Jumo 004 cough

[Rjel]

1 hour ago, [CPT]Crunch said:

Might work on the first bullet, but the rapidly following next 20 not so much.

 

53 minutes ago, Eisenfaustus said:

They don’t go all through the same hole. Not on the ground and Especially not in s WWII aerial dogfight. 

No, obviously they don't. But, I think Crunch's point is valid. While they don't go through the same hole, they also don't hit the same obstruction either. Some might hit a spar or other heavier part, while the next might well pass cleanly through hitting nothing but lightweight skin until it too hits some other vital part. The cumulative effect is what I appreciate. It's all apples and oranges but Pat said earlier, the .50 was the perfect choice for the airwar the U.S. services fought as its enemies never presented the same type of massed bomber formations the Axis faced.

[JtD]

36 minutes ago, Mtnbiker1998 said:

almost looks like 30% of the bullets did in fact penetrate the armor at 200 yards

 

On a Bf109F-4, and only 30% of the rounds hitting above fuel level. Assuming the Bf109 does not fly on an empty tank, this figure goes down considerably in practice. This figure would be further reduced on later models due to an additional bulkhead, iIrc.

 

On a Fw190 the 0.50 AP was tested with 0% probability of defeating pilot armour in attacks from behind (up to 5° off dead 6).

 

Overall, pilot armour was fairly effective, but certainly not undefeatable. Had it not been effective, it would have been removed, and had it given the Luftwaffe fighters a significant practical immunity, the Allied guns would have been upgraded. It should also be considered that there are plenty of other things on a fighter which can be hit in order to disable it. So as much fun as theoretical debates "will it or will it not penetrate" are, in practice they are not that relevant (unless you're the pilot behind the plate).

 

What Jaws is pointing at - you've got the unit wrong, a 0.50 does around 3000fps muzzle velocity, which is around 900m/s, not 3000m/s as you stated. That's railgun territory.

[Mtnbiker1998]

5 minutes ago, JtD said:

What Jaws is pointing at - you've got the unit wrong, a 0.50 does around 3000fps muzzle velocity, which is around 900m/s, not 3000m/s as you stated. That's railgun territory.

Thus why I hate people using the Metric system for American planes. Imperial units are standard in aviation

[Voidhunger]

On 2/2/2022 at 7:40 PM, Rjel said:

All I can say is wow. I've never had a chance to fire a .50 cal but I would love to. If this round can hole heavy rail stock like this, an engine block shouldn't have been any tougher to penetrate in most places. As to any seat armor in R/L 109s or 190s, I can't see those having been any more durable. 

 

I like the .50s we have in the sim in their current incarnation. It took a few weeks for the new dispersion patterns to feel right for me but now I'm pretty pleased. Once we get APIs, you'll not pry me away from any U.S.A.A.F fighters. IF we ever do get to go to the P.T.O, they'll be absolutely devastating against Japanese A/C, as they obviously were in real life. 

 

If the mods feel this post should be moved, feel free.

If I remember correctly there was a nice picture in this book of punctured track rail from the 50cal when the US fighter attacked train in CZ.

https://www.academia.cz/pod-palbou-hloubkaru--vojtasek-filip--academia--2019

 

[Jaws2002]

On 2/3/2022 at 12:50 PM, Mtnbiker1998 said:

Many different varieties of modern .50 BMG out of long barrels can hit that. go look it up yourself. far from the "LoL ePiC fAiL" you were hoping for there bud. So the velocity of an aircraft M2 firing ww2 loads might be slightly different, its frankly nitpicking (the wrong numbers sure seemed ok for the devs for how long?) Its a very heavy bullet going very, very fast and it retains that energy very well. Thats literally the whole point of the round. sue me. At least I googled, more than the average idiot here can say.

 

 

Dude, 3000 m/s is almost 10.000 f/s. That's almost Mach 9! 

On 2/3/2022 at 12:50 PM, Mtnbiker1998 said:

but it almost, almost looks like 30% of the bullets did in fact penetrate the armor at 200 yards.

 Yes. That's still a far cry from your 2000 meters.  When the fuel tank was empty, or the hit was above the fuel level. If the hits were below the fuel level they didn't get to the pilot.  

 

On 2/3/2022 at 12:50 PM, Mtnbiker1998 said:

and still the expected amount of neural backflips from the likes of you.

Where in my post did you see me complain about  .50cal damage?  I was just pointing out, that terminal ballistics are more complicated than looking at a penetration table and dismissing what the bullet has to go through, before it gets to the armor.

I don't really care either way about how this is modelled in game.  Ten-fifteen percent, in either way means nothing. I don't play that much anymore, I didn't play online for many years and I've been here long enough to become immune to this kind of Fm/DM vitriol.  

 

Ballistics are a complicated science, with a lot of variables.

 

Here's a 152mm cannon shell, being deflected by.... a few melons. Explain that with your simplistic ballistics.

 

    

[Mtnbiker1998]

9 minutes ago, Jaws2002 said:

 

I don't really care either way about how this is modelled in game.  Ten-fifteen percent, in either way means nothing. I don't play that much anymore, I didn't play online for many years and I've been here long enough to become immune to this kind of Fm/DM vitriol.  

    

I adjusted my typo. It was exactly that, a typo. if that low hanging fruit is the only thing in my post you can use against me, then I'm feeling pretty good. 

 

And yet here you are, saying how much you don't care and obviously implying how morally and intellectually superior that makes you, and yet here you are, still replying. How incredibly high and mighty of you.

 

I ain't delusional either, look at the myriad past threads about .50 cals,  and you see exactly what I'm talking about. Every time. .50 cals are either perfect Armor penetrating hole punchers, or useless tumbling hunks of lead, all depending on whether people are talking about Aero Damage or Pilot armor respectively. Its a hilarious flipping of narrative from Luftwhiners who love their German Engineering and Europeans online who love to trash anything American for no reason other than it being American. You'll see the naysayers who always comment on those threads with that same garbage. Maybe if you'd used the same level of reading comprehension you used to pounce on a typo, you'd know I wasn't talking about you exclusively.

 

If you really are "immune," do me a favor and stop replying. Your useless drivel is getting old.

 

As a side note since you made your edit while I was replying, LOL. Apparently a modern .50 cal and a rail is a bad analog and should be completely ignored, but a tank shell hitting melons? SCIENCE!

Edited February 3, 2022 by Mtnbiker1998

[Jaws2002]

20 minutes ago, Mtnbiker1998 said:

Apparently a modern .50 cal and a rail is a bad analog and should be completely ignored, but a tank shell hitting melons? SCIENCE!

 

 Yes it is, because there's nothing between the gun and the rail, while in aircraft, the armor is inside. The bullet has to pass through stuff to get to it.  There's a reason they installed so many guns on this planes. 

  I don't care about game damage model. This was about physics. 

 

Edited February 3, 2022 by Jaws2002

[Mtnbiker1998]

On 2/3/2022 at 2:17 PM, Jaws2002 said:

 

 Yes it is, because there's nothing between the gun and the rail, while in aircraft, the armor is inside. The bullet has to pass through stuff to get to it.  There's a reason they installed so many guns on this planes. 

  I don't care about game damage model. This was about physics. 

 

And yet again, you only address one single point of what I said, and completely miss the point entirely. (Edit for personal insults - Mr Smith) You're proving that everything I've said in this thread is spot on.

[CUJO_1970]

On 2/2/2022 at 2:50 PM, Rjel said:

Interesting points to be sure. For all the same reasons, I always think the same thing when the Youtube video is trotted out here showing the 30mm cannon ripping up a Spitfire fuselage from nearly point blank range as proof it under performs in this sim.

Well, it was the Royal Air Force that originally “trotted that out” to show what the 30mm round was doing to their actual aircraft. The denial we read about on the forums regarding that test is just that…denial. 

 

The range typically has nothing to do with it as those 20mm and 30mm rounds rely on chemical/gas pressure more than kinetic energy to do their damage. Once the round penned the aircraft and the fuse is set off, whatever the range, it was going to release the same energy…whether from 700 yards or 7 yards. 

[the_emperor]

27 minutes ago, CUJO_1970 said:

The range typically has nothing to do with it as those 20mm and 30mm rounds rely on chemical/gas pressure more than kinetic energy to do their damage. Once the round penned the aircraft and the fuse is set off, whatever the range, it was going to release the same energy…whether from 700 yards or 7 yards. 

 

correct. the German HE Mineshells are of different design and rely on blast effect which is further increased by a delay charge to let the shell go off inside the highly stressed  monocoque airframe. Airframes which employ wood or fabric structure e.g. the Hurricane are a bit less effected. Kinetic energy/mass/velocity dont play a big role in the design of the shell as a means to deliver damage and so it has neglectable  AP perfomance. 

[FuriousMeow]

Wasn't reliability, or lack thereof, in US produced 20mm weapons the reason US stuck with .50s for WWII?

[6./ZG26_Custard]

5 hours ago, Jaws2002 said:

A heavy, tumbling bullet will still cause a lot of damage, spall and shrapnel, but it's ability to penetrate armor, after it hit something else,  will be drastically reduced.

Rounds certainty seem to be traveling in a dead straight line.

 

An interesting snippet from the author of Flying Guns: World War II: Development of Aircraft Guns, Ammunition and Installations 1933-45, discussing the 20 mm Ho-5 and 99 -2 cannons

 

Re: US seat back armour vs Ho-5 or 99-2 cannon?

 

Posted By: Tony Williams <Tony.Williams@quarry.nildram.co.uk>
Date: Thursday, 11 July 2002, at 12:39 a.m.

 

I don't know about the armour protection, but the Type 99-2 should have been capable of penetrating up to 30mm armour at short range (the Ho-5 perhaps 20-25mm).

However, these figures would be against armour in the open. In practice, AP projectiles were much less effective against aircraft because they had to plough through the structure before reaching the armour, and this not only slowed them down but often made them tumble so they hit sideways, drastically reducing effectiveness.

 

Tony Williams

 https://j-aircraft.com/faq/aircraft_weapons.htm#Aircraft Weapons

[Jaws2002]

19 minutes ago, FuriousMeow said:

Wasn't reliability, or lack thereof, in US produced 20mm weapons the reason US stuck with .50s for WWII?

Yep.  US actually bought the license for the 20mm Hispano cannon and built a new ammo  plant, specially for this. Then When they converted the gun to imperial from Metric, things took a bad turn. 

   The Hispano 404 cannon was a version of the Oerlikon, 20mm cannon, modified by the Hispano-Suiza, to work as engine cannon. The gun needed some modifications to work properly in wing mountings.

The British got most of the problems fixed in their version, the Hispano MkII and offered the drawings to the Americans. The Americans declined and did their own unit conversion and modifications. 

   That decision, and the long time it took them to sort of fixing the problem,  doomed the guns for most of the war.  They worked Ok in P-38 nose, but not good enough for wings.

[Winkysmith]

3 hours ago, Mtnbiker1998 said:

Thus why I hate people using the Metric system for American planes. Imperial units are standard in aviation

Uh, sorry, but Nautical units are standard for aviation in any part of the world.

[Mtnbiker1998]

15 minutes ago, Winkysmith said:

Uh, sorry, but Nautical units are standard for aviation in any part of the world.

Which is much closer to the Imperial system than the Metric one.. And check what your Altimeter reads in

[BlitzPig_EL]

Nautical measurements is a more modern evolution in aviation.  The USAAF used standard Imperial units (though US gallons for fuel) for speed and altitude, but then you have the IJN who used knots for speed and meters for altitude.  

[Jaws2002]

After using both systems,  the metric system is soooo much more simple.  Any conversions you need to make,  you just move the decimal left or right. In imperial you have to multiply and divide, by different numbers, depending on what units you have to convert.

[BlitzPig_EL]

I jump between metric, SAE and Whitworth tools all the time. No big deal.  The BlitzPigs have members from all over the place, so dealing with metric stuff isn't a big deal, the only thing I'll never understand are "stone" as a unit of measure, or X number of CWT. (Hundredweight)  A hundred what exactly?

 

Then there is Russian Imperial distance marking on my Model 91 Mosin "Three Line Rifle".  

 

Fun stuff.

[357th_KW]

14 hours ago, Jaws2002 said:

 

Are you sure about that? go do more digging, because you failed miserably. 

 

 

 My granddaddy didn't hunt with .223, because it wasn't even invented back then  and most of today's .50 cal is not the same thing they were shooting back in ww2.

 The vast majority of WW2 ammunition was  replaced with newer, more performant loads. In most cases the new loads are faster and hit their intended velocity from much shorter barrels. New powers, new metallurgy, new bullet construction...

      

 

 

 

 

There's stuff behind the pilot in most planes, you know. I had a ww2 test somewhere, exactly about the penetration behind aluminum sheet, but I didn't find it.

I did find this report that is relevant to the discussion. 

 

 

See that? If there's fuel in the tank and the fuel level is above the hit point, .50 cal AP can't get to the pilot at 200 yards! 

 

 

 

 

There are some important considerations to take into account with this test.  Note the date, July 1942 (and realistically the test likely took place some time before the report was published).  British .50 AP ammo was based on the US M1 AP round (the forerunner to the US M2 AP used during WWII) and used a heavier 750 grain bullet with a 2500 fps muzzle velocity (in fact some of it was built in the US for them to that older M1 spec).  The US M2 AP round used a 708 grain projectile with a muzzle velocity of 2835 fps (see page 136, 139 and 140 of this US Ordnance document).  The British eventually cloned the US M8 API (armor piercing incendiary, with penetration very close to the M2) in 1944 per the first link, and M2 in the 1950's.

 

It's worth noting in the next paragraph that 20mm Hispano Ball ammunition can still pierce the 109F's armor with a strike below the fuel line in 20% of cases - per the table in this link, that 20mm Ball ammo was only rated to penetrate 12mm at 200yds at 0 degrees against a hardened plate (it's described as 14mm earlier in the text).  The 20mm AP Mk II which they note is fully capable of penetrating the armor regardless of fuel level is rated at 27mm.  In that same scenario, drawing from the US Ordnance charts, M2 .50 from a 36 inch barrel (standard AN/M2) will defeat 20.8mm of hardened plate.  Obviously there would have been some differences in the British and US test protocols, but we can easily see that the M2 would have significantly more penetration then the M1 or the 20mm ball.

 

The other piece to note, is that this is armor from a 109F-4, likely built in 1941 (the materials had to be produced, assembled, sent to a front line unit, used in combat for some period and then captured by the Brits, shipped to the testing site, tested etc all prior to July 1942).  The makeup of German armor changed as the war went on, due to the loss of access to nickel and molybdenum.  Consumption of those metals was heavily reduced in 1942 as a rationing measure (to allow for increased overall production with the limited resources that were available) and a lot of supply dried up with the loss of access to North Africa early in 1943.  As a result, captured German aircraft armor in 1941 was high hardness, while captured German armor in 1944 was softer, rolled homogeneous armor.  As you can see from the US Ordnance tables, this raises the penetration value of M2 AP to around 23.9mm at 200yds and 0 degrees.

 

TLDR - our .50 AP ammo in game was closer in penetration performance to the 20mm AP in that test, and well beyond the 20mm ball, and the armor plates in late war German aircraft were softer then those present in that 109F.

[the_emperor]

12 hours ago, FuriousMeow said:

Wasn't reliability, or lack thereof, in US produced 20mm weapons the reason US stuck with .50s for WWII?

 

And logistics, with the .50cal you have one weapons system, that is supplied to Bombers, fighters, and (in a different version) to ground forces in short, basically every armed service of the US. That easies up everyhting (standardization is key),  productions, spareparts, crew training, ammunition supply etc. and it was a system with which the US Services were already familiar with. That let the them field a HMg very fast in vast quantities in high quality. And it was and still is a highly potent weapon, especially when it comes in batteries of 4-8.

Edited February 4, 2022 by the_emperor

[[CPT]Crunch]

Except it didn't quite work out that way, toward the end of the war you had three different variants of .50's in M-2's and an M-3 air gun, with only about 20% spare parts interchangeable between the M-2's and zero with the M-3.  But M-3 for the win, faster cyclic rates in excess of 1000 rpm's with higher velocity ammo performance over 3000 fps.  Hope we see those some day for March 45 and beyond.