German Firing Tests with Russian and British Guns and Ammo

[rexford]

Miles Krogfus has discovered a graph that appears to present 1942 German firing tests of captured Russian and British guns and ammo.

The graphed penetration data at 30° from vertical equals:

=========================================

Russian 57mm anti-tank gun: 88mm at 100m, 83mm at 500m, 77mm at 1200m

Russian 76.2mm tank gun: 60mm at 100m, 51mm at 500m, 45mm at 1200m

Russian 45mm anti-tank gun: 40mm at 100m, 28mm at 500m, 18mm at 1200m

Russian 45mm anti-tank gun: 71mm at 100m, 48mm at 500m (looks like HVAP)

British 6 pdr tank gun: 70mm at 100m, 59mm at 500m, 49mm at 1200m

British 2 pdr anti-tank gun: 40mm at 100m, 28mm at 500m, 18mm at 1200m

Analyzing the data required a number of assumptions after reviewing the information, researching published WW II data and trying various alternatives:

1. All of the ammo appears to be uncapped AP rounds except Russian 57mm and 76.2mm APBC, and 45mm HVAP. This is consistent with the ammo types prevalent during 1942. 76.2mm APBC may be BR-350A.

2. Data is based on five or more consecutive penetrations, which represents close to 100% success probability and was a German standard for defining penetration.

3. The plate thickness for 50% success is about 21% greater than the 100% success thickness. Due to variations between rounds and experimental variations the actual difference for individual ammo types could be as low as 12% to 14% (0° penetration estimates could be high by about 7% in some cases).

4. Test armor appears to be face-hardened

Applying the above assumptions to the data with slope effect multipliers from our book (Armor & Gunnery) results in the following 0° penetration figures for 50% success (half penetrate, half don’t):

Estimated Penetration at 0° from Vertical with 50% Success

===========================================

Russian 57mm anti-tank gun: 129mm at 100m, 121mm at 500m, 112mm at 1200m

Russian 76.2mm tank gun: 83mm at 100m, 70mm at 500m, 61mm at 1200m

Russian 45mm anti-tank gun: 56mm at 100m, 38mm at 500m, 23mm at 1200m

Russian 45mm anti-tank gun: 115mm at 100m, 77mm at 500m (looks like HVAP)

British 6 pdr tank gun: 109mm at 100m, 91mm at 500m, 73mm at 1200m

British 2 pdr anti-tank gun: 56mm at 100m, 38mm at 500m, 23mm at 1200m

Comparison with face-hardened penetration estimates from the Russian ARTKOM equation and published British data suggests that the above estimates for 0° penetration by AP and APBC are fairly consistent with national figures. It is possible that the Germans used a method with fewer than 5 consecutive successes for HVAP, so the above estimate for 45mm HVAP against face-hardened armor is highly suspect.

The above estimates for Russian 76.2mm are very close to the ARTKOM equation estimates after they are converted to 50% success (80mm at 100m, 72mm at 500m, 63mm at 1200m).

The 57mm APBC penetration drop-off with range is not consistent with Russian estimates of velocity vs range and may include an error of some sort (penetration on graph drops off too slowly).

It is worth noting that neither the Russian 45mm or British 40mm guns would be expected to penetrate the 50mm face-hardened plates on the front of PzKpfw III and IV tanks at 500m range with uncapped AP.

[Jambrosic]

Excellent info. I will have to cut and paste this for future reference.

Kromyr

[Kromyr]

Oh btw I did post the message under the last username. Sorry if there was any confusion.

Kromyr

[rexford]

Here is a comparison of the German estimates converted to 0° penetration and 50% success versus Russian data at the same angle for the same guns (face-hardened armor appears to apply in both cases):

British 6 pdr AP

100m: 109mm German est. vs 103mm Russian

500m: 91mm German vs 90mm Russian

British 2 pdr AP

100m: 56mm German and Russian

500m: 38mm German vs 40mm Russian

Russian 76.2mm Tank Gun (APBC)

100m: 83mm German and Russian

500m: 70mm German vs 72mm Russian

Note: There is a possibility that the Russian penetration test figures are based on super-hardened BR-350B and should be increased by 6%.

Russian 57mm Anti-Tank Gun (APBC)

100m: 129mm German vs 114mm Russian

500m: 121mm German vs 100mm Russian

The Russian penetration data is not flagged as to whether it represents 80% success (6% thinner than 50% success thickness), 20% success (6% thicker) or the average of 20% and 80% (which would be 50%).

[YankeeDog]

Interesting stuff. Thanks for posting, Rexford.

One quick question: Do you have any information/educated guess as to what definition of "penetration" was in these test? I know many Russian tests set the benchmark as at least 80% of the mass of projectile to have penetrated and be found inside the AFV, but I know far less about what standard the Germans used.

Thanks,

YD

[rexford]

Originally posted by YankeeDog:

Interesting stuff. Thanks for posting, Rexford.

One quick question: Do you have any information/educated guess as to what definition of "penetration" was in these test? I know many Russian tests set the benchmark as at least 80% of the mass of projectile to have penetrated and be found inside the AFV, but I know far less about what standard the Germans used.

Thanks,

YD

Good question.

The Germans required that the HE burster in the round be able to detonate on the other side of the armor, which suggests that almost all of the round had to get completely through and damage to the ammo would be minimal.

A U.S. study of penetration criteria found that the percentage of the round which had to pass completely through the plate did not have much impact on the thickness. The criteria that a certain percentage of the round has to pass through for a successful hit is there to make sure that a hit where the round sticks in the plate, but a tiny portion of the nose breaks off and makes it through, is not counted as a success.

[John Kettler]

rexford,

I must respectfully disagee with your assumption that almost all of the AP shell had to be on the far side of the armor plate at detonation in order to be effective. British Operational Research in the Western Desert found that a penetration of half the projectile body to the far side of the plate, followed by detonation of the AP shell, was generally enough to destroy the tank and shred the crew. By contrast, the British found that their projectile penetrations left a readily repairable tank and did little to the crew. I posted this info some time ago in one of the gunnery threads, but have not been able to find it again. Maybe John D.Salt can help, using his seemingly inexhaustible supply of PRO goodies.

Regards,

John Kettler

[rexford]

Originally posted by John Kettler:

rexford,

I must respectfully disagee with your assumption that almost all of the AP shell had to be on the far side of the armor plate at detonation in order to be effective. British Operational Research in the Western Desert found that a penetration of half the projectile body to the far side of the plate, followed by detonation of the AP shell, was generally enough to destroy the tank and shred the crew. By contrast, the British found that their projectile penetrations left a readily repairable tank and did little to the crew. I posted this info some time ago in one of the gunnery threads, but have not been able to find it again. Maybe John D.Salt can help, using his seemingly inexhaustible supply of PRO goodies.

Regards,

John Kettler

[rexford]

Originally posted by John Kettler:

rexford,

I must respectfully disagee with your assumption that almost all of the AP shell had to be on the far side of the armor plate at detonation in order to be effective. Regards,

John Kettler

Maybe I wasn't too clear because I meant something else. The following will hopefully clear up what I meant.

The German criteria during their penetration tests was that the round had to penetrate the plate with the HE burster intact and capable of detonating. If the round penetrated and the HE burster was damaged the round was not credited with a penetration.

[Bastables]

Originally posted by John Kettler:

rexford,

I must respectfully disagee with your assumption that almost all of the AP shell had to be on the far side of the armor plate at detonation in order to be effective. British Operational Research in the Western Desert found that a penetration of half the projectile body to the far side of the plate, followed by detonation of the AP shell, was generally enough to destroy the tank and shred the crew. By contrast, the British found that their projectile penetrations left a readily repairable tank and did little to the crew. I posted this info some time ago in one of the gunnery threads, but have not been able to find it again. Maybe John D.Salt can help, using his seemingly inexhaustible supply of PRO goodies.

Regards,

John Kettler

Those tests and their conculsions appear in Jentz's: Tank combat in North africa. Major Jarrett states on german APHE : "These projectiles at long range need only to obtain a partial penatration and the explosive charge can compleate the destruction of at least the tank crew. At closer ranges the destructive effect is very great, where in many cases the destruction of the tank is permanent."

One can infer that the further the APHE shell enters the tanks dead space, before the charge is set off the greater the overall damage.

The same book also has extracts of German explanations of their armour penatration curves including the statement : "thus only the complete penatration with the total effect inside the tank is considred." (1998 Jentz p48).

These bits tend to support Rexfords ideas on what the Germans considred "penatration."

[ July 19, 2004, 07:50 AM: Message edited by: Bastables ]

[rexford]

The German definition of a complete penetration that I used in my posts came from the British BIOS report, where they interviewed captured German arms and armament workers, researchers and theorists during and after the war.

Very interesting that a partial penetration could result in significant crew injuries within a tank. Did not know that.

One other interesting point is that British firing tests with German 75mm and 88mm APCBC showed that the HE burster was not working on 45° and 55° angled hits (measured from perpendicular or vertical). Penetration of highly sloped plate results in a large cross stress on the projectile body, since they are first rotated upwards as in a ricochet and then they turn downwards and penetrate in a downward motion nose first as the plate gives way.

Page 15 in the Panther Fibel presents some photo's of rounds penetrating plate at various angles, and the 45° pictures show how the round is first moved upward and then passes through the plate moving downwards. The penetration at 30° from vertical also changes direction from upwards upon initial impact to horizontal after penetration.