German Firing Tests with Russian And British Guns/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

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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.

[MikeyD]

I was utterly amazed to read the Brit 2 pdr and Russian 45mm running neck-and-neck! I Somehow doubt they do so when comparing the in-game CMAK 2 pdr to the CMBB 45mm, though I'll have to go home and double-check. Of course the Russkies had a longer gun tube length for their later 45mm gun. Their HE and schrapnel rounds would seem to make the gun considerably more useful than the Brit weapon.

So, after alll this time denegrating the poor Russian 45mm gun it turns out to be roughly on par with contemporary weapons after all! Unless that graph was only a rough estimate based on a penetration formula. After all, the first line of the post has the phrase "...appears to present..." in it.

[flamingknives]

Good point, is it known which 45mm gun it was. I don't recall the in-service dates for the longer barrelled weapon.

[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%).

[rexford]

Originally posted by MikeyD:

I was utterly amazed to read the Brit 2 pdr and Russian 45mm running neck-and-neck! I Somehow doubt they do so when comparing the in-game CMAK 2 pdr to the CMBB 45mm, though I'll have to go home and double-check. Of course the Russkies had a longer gun tube length for their later 45mm gun. Their HE and schrapnel rounds would seem to make the gun considerably more useful than the Brit weapon.

So, after alll this time denegrating the poor Russian 45mm gun it turns out to be roughly on par with contemporary weapons after all! Unless that graph was only a rough estimate based on a penetration formula. After all, the first line of the post has the phrase "...appears to present..." in it.

The 45mm ammo appears to be uncapped AP due to the face-hardened penetration thicknesses and the rate at which penetration falls off with range.

The 45mm APBC round would penetrate more face-hardened armor and the penetration would fall off slower.

My book estimates for 2 pdr AP face-hardened performance have 50mm at 0° and 500m, not around 40mm.

[rexford]

Originally posted by MikeyD:

I was utterly amazed to read the Brit 2 pdr and Russian 45mm running neck-and-neck! I Somehow doubt they do so when comparing the in-game CMAK 2 pdr to the CMBB 45mm, though I'll have to go home and double-check. Of course the Russkies had a longer gun tube length for their later 45mm gun. Their HE and schrapnel rounds would seem to make the gun considerably more useful than the Brit weapon.

So, after alll this time denegrating the poor Russian 45mm gun it turns out to be roughly on par with contemporary weapons after all! Unless that graph was only a rough estimate based on a penetration formula. After all, the first line of the post has the phrase "...appears to present..." in it.

The face-hardened penetration data for the Russian 45mm anti-tank gun is consistent with our estimates for the M1937 model with L46 barrel length, which fired AP at 760 m/s. 2 pdr AP was fired at 792 m/s but was a smaller and lighter round.

45mm AP weighed 1.43 kg while 2 pdr AP weighed 1.077 kg.

There is a possibility that the 45mm anti-tank gun was the Model 1942 with a barrel length of L66 (I think) and a muzzle velocity of 820 m/s.

[MikeyD]

The difference between Brit 6 pdr (57mm) and Russian 57mm is striking too, especially a longer ranges. 73mm vs 112mm at 1200m range? That's quite a respectable gap. I know in-game the Russian 57mm gun is a killer. Too bad CMBB didn't include the Lend-Lease SU-57 (the American 6 pdr on a halftrack chassis). Then we'd be able to do proper side-by-side comparisons between guns.

[flamingknives]

Some of the Vals and the Churchill III in CMBB mount 6pdr guns.

The 6pdr is L47(?) while the Soviet 57mm is ridiculously long by comparison.