Interesting that the T33 APBC вЂ“ in spite of its lack of a penetration cap вЂ“ shows decreasing ballistic limits vs. It appears that 50mm AP rounds were shatter failing against the 40.9mm plates even though they possessed more than enough penetration to defeat the armor. 40.9mm at 40В° should resist 50mm AP like 63mm, and less when high hardness deficiencies are considered. Interestingly enough, when 50mm AP hit 40.9mm high hardness plates at 40В°, two of five hits failed even though the armor resistance was well below the penetration of 50mm AP at 100m. high hardness armor, and are reasonably consistent with reported penetration ranges in Jentz' works. Granted we are talking about a handful of firing test results, but the German tests are consistent with the equations prepared using U.S. Livingston, estimates that 45mm high hardness plate resists with 83% of 240 Brinell armor against 50mm hits. WW II BALLISTICS: Armor and Gunnery, by L. However, if 47.3mm of high hardness armor resists with 83% of the resistance of 240 Brinell armor when it is hit by 50mm rounds, then the 1-in-3 penetration ratio is supported. If 47.3mm of 240 Brinell plate at 60В° is estimated as equivalent to 123mm at 0В° on 50mm AP hits, then the penetration/armor resistance ratio is only 0.80. The abovementioned results suggest a 1-in-3 complete penetration ratio when 50mm AP struck 47.3mm at about 60В°, which requires a penetration/armor resistance ratio of about 0.98. Partial penetrations were obtained against 47.7mm at 59В° and 47.1mm at 59.5В°.

The German 50mm AP round fully penetrated 47.2mm at 60.5 degrees, and 42.1mm at 65 degrees, during the tests. High hardness armor is going to be less resistant than 250 Brinell plate when the projectile diameter exceeds the armor thickness, due to low impact resistance and brittle structure (high hardness requires crystalline structure which is brittle and subject to rapid failure, 250 Brinell will be fibrous and ductile when carefully mixed and produced). Reports on T34 armor also show undesirable elements as well.Дuring 1942, the Germans reproduced T34 armor with the same composition and heat treatment, and fired 37mm and 50mm tank guns against the plate at various angles (100m range). high hardness armor was similar to Russian. This was one of the factors we considered when we assumed that U.S. When our penetration range estimates for T34 against 75L43 APCBC are compared with actual combat reports in Thomas Jentz' Panzertruppen books, the estimates present reasonable agreement with reports. The estimates in our book for high hardness armor resistance are based on equations drawn from U.S. tests against high hardness armor were conducted with 'decent' quality armor: defeated armor in tests that described armor failure modes did not suggest poor armor characteristics. The 90mm T33 tests at 70В° showed that a 2' plate at 280 Brinell presented 86% of the resistance offered by 3' at 360 or 400 Brinell plate. Livingston), 45mm armor at 400 Brinell would resist like 34mm of 280 Brinell plate when it is hit by 75mm rounds (slope effects based on the actual 45mm thickness). Based on our research (which is presented in WW II BALLISTICS: Armor and Gunnery, by L. When 45mm high hardness armor (400 Brinell) is hit at a 60В° angle by 75m German rounds, the T/D ratio is 0.60 (45mm/75mm) and the armor would be expected to resist with less than 85% of the resistance offered by 280 Brinell plate. Since penetration tests are conducted against armor with about the same resistance as 280 Brinell plate, this means that 400 Brinell armor is going to lose substantial resistance when the T/D ratio is 0.85 or less. When 90mm T33 APBC strikes 3' armor the thickness/diameter ratio (T/D) is 0.85, and 400 Brinell Hardness armor at 60В° resists with about 85% of the 0В° resistance of 280 Brinell plate((2348 fps/2629 fps) raised to 1.4 power). What does this mean for WW II penetration range estimates against tanks with high hardness armor, like the T34, T34/85, SU 85 and SU 100? The Army Protection Limit varies with armor hardness in the following manner at angles from 60В° and 65В° against 3' plate:Дў629 fps against 280 Brinell, 2554 fps against 360 Brinell and 2348 fps against 400 BrinellДЈ026 fps against 280 Brinell, 2948 fps against 300 Brinell and 2870 fps against 320 Brinell We recently received excerpts from a WW II Aberdeen Proving Grounds reports on the penetration of 90mm T33 APBC rounds as a function of armor thickness, angle and brinell hardness.

Wwii ballistics armor and gunnery