rexford Posted March 28, 2004 Share Posted March 28, 2004 The following data pertains to WW II Russian 85mm and American 76mm HVAP rounds: Russian 85mm HVAP ================= Fired at 1040 m/s 0.65 kg tungsten core 27.94mm core diameter in American analysis, 27.77mm from Russian data. 100m, 1009 m/s, 165mm vertical target penetration 300m, 947 m/s, 150mm 500m, 887 m/s, 137mm 1000m, 744 m/s, 107mm 1500m, 614 m/s, 81mm American 76mm HVAP ================== Fired at 1037 m/s 1.765 kg tungsten core 38.1mm core diameter 100m, 1018 m/s, 240mm vertical target penetration 300m, 981 m/s, 226mm 500m, 939 m/s, 211mm 1000m, 848 m/s, 179mm 1500m, 756 m/s 149mm Comparing the two HVAP rounds the American 76mm ammunition holds a greater percentage of its muzzle velocity at range and also outpenetrates 85mm HVAP by a significant amount. The American HVAP tungsten core is larger and heavier than the Russian core. The British 17 pdr APDS tungsten core had similar dimensions and weight when compared to the American 76mm HVAP. The above data shows that larger guns did not always fire more effective tungsten core ammo during WW II. The American HVAP penetration velocity and penetration data is from TM9-1907, the Russian 85mm HVAP figures were provided by Miles Krogfus. If the Russian tungsten core data and velocity is used for penetration estimates based on the U.S. 76mm HVAP at 0m and 0 degrees (247mm penetration at 1037 m/s), the resulting DeMarre equation estimates are: 100m, 163mm predicted (165mm actual) 300m, 149mm predicted (150mm actual) 500m, 136mm predicted (137mm actual) 1000m, 106mm predicted (107mm actual) 1500m, 80mm predicted (81mm actual) The Russian 85mm HVAP tungsten core was expected to perform with the same ballistic characteristics as the American 76mm HVAP, which suggests a similarity of material quality. Previous posts on this forum regarding Russian 45mm and 76.2mm HAVP (or APCR) showed that the ammunition performed with the same ballistic penetration characteristics as American 76mm HVAP beyond close range, but the Russian tungsten cores appeared to perform in an inferior manner once the impact velocity exceeded about 700 m/s. 0 Quote Link to comment Share on other sites More sharing options...
John Kettler Posted March 29, 2004 Share Posted March 29, 2004 rexford, Can't speak for the rest of the troops, but that is certainly not the intuitive result I'd expect. How do the guns stack up in terms of penetration with the typical AP shell for each? Keep up the great work! Regards, John Kettler 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted March 30, 2004 Author Share Posted March 30, 2004 The U.S. 76mm HVAP and British APDS rounds (combat and experimental) used tungsten cores which were half the diameter of the carrier (76.2mm 17 pdr APDS fired a 38.1mm tungsten core). Russian tungsten core diameters appear to assume a lower percentage of the carrier diameter as the gun size increases: 45mm: 19.1mm core and 45mm carrier, 42.4% core-to-carrier percentage 57mm: 24.1mm core and 57mm carrier, 42.3% 76.2mm: 27.94mm core and 76.2mm carrier, 36.7% 85mm: 27.77mm core and 85mm carrier, 32.7% The relationship between core and carrier diameter may have been related to tungsten conservation, although other factors are possible. The Russian 76.2mm tungsten core round used a 0.484 kg tungsten core with a 0.149 kg steel follow-up plug which would add its full weight to the penetration of vertical plates as if it were tungsten, and which may have been a conservation effort. It is also noted that the Russians stayed with the arrowhead type of tungsten core HVAP round after the Germans switched. 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted March 30, 2004 Author Share Posted March 30, 2004 Originally posted by John Kettler: rexford, Can't speak for the rest of the troops, but that is certainly not the intuitive result I'd expect. How do the guns stack up in terms of penetration with the typical AP shell for each? Keep up the great work! Regards, John Kettler The U.S. 76mm APCBC round was compared to the 85mm APBC during a Russian firing trial against a captured Tiger II, and the U.S. gun was significantly better at penetrating the Tiger II. The report is published on the Russian Battlefield site. Comparing Russian 85mm HVAP to 85mm APBC against vertical targets results in: 100m: 165mm for HVAP, 139mm for APBC 500m: 137mm for HVAP, 123mm for APBC 1000m: 107mm for HVAP, 105mm for APBC 1500m: 81mm for HVAP, 91mm for APBC Inside 500m, 85mm HVAP has a higher probability to defeat the Tiger mantlet than 85mm APBC. For U.S. 76mm APCBC: 100m: 239mm for HVAP, 125mm for APCBC 500m: 208mm for HVAP, 116mm for APCBC 1000m: 175mm for HVAP, 106mm for APCBC 1500m: 147mm for HVAP, 97mm for APCBC 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted April 1, 2004 Author Share Posted April 1, 2004 The following site has some info which indicates that Russian tungsten core ammo contained mercury compounds which could vaporize after penetration, injuring or killing crew members: http://www.geocities.com/Pentagon/Base/1852/57mm.html 0 Quote Link to comment Share on other sites More sharing options...
Colonel J Lee Posted April 1, 2004 Share Posted April 1, 2004 Is this the same 85mm Russian gun that was used by the T34/85s? If so, I am surprised the US 76mm is that much better. 0 Quote Link to comment Share on other sites More sharing options...
flamingknives Posted April 1, 2004 Share Posted April 1, 2004 It's pretty obvious when you compare the make-up of the shells. The US shot travels as fast and weighs almost three times as much but is only 37% wider. 0 Quote Link to comment Share on other sites More sharing options...
meldorian Posted April 1, 2004 Share Posted April 1, 2004 Still, it is rather amazing that the US standard AP round is better than the Russian one. The Russian one is not only heavier, according to the data in CMBB it also has a slightly higher muzzle velocity. I would certainly expect it to penetrate better than the 76mm AP round, just because its kinetic energy should be somewhat higher. 0 Quote Link to comment Share on other sites More sharing options...
mrcoffee Posted April 2, 2004 Share Posted April 2, 2004 In the Russian website http://www.battlefield.ru/ one of the authors states that russian designers failed in trying to increase muzzle velocity. Instead, the designers increased the weight of the shell by increasing the calibre. I would guess that's why Russian tanks guns were so commonly huge--sheer weight of shot performes the equivalent of "them fine German guns." Also, really large calibre guns work well against infantry, which is what the ammo load of most Russian tanks had. 0 Quote Link to comment Share on other sites More sharing options...
K_Tiger Posted April 2, 2004 Share Posted April 2, 2004 Seems, the US 76mm with wolfram/tungsten ammo does not need to worry about to engage a KTiger frontaly.... it would easy defeat the Turret front from 0-700 meter. Also, the Performance with tungsten is nearly the same like from the 75/L70... does this mean the US Ammo was better in this case? 0 Quote Link to comment Share on other sites More sharing options...
flamingknives Posted April 2, 2004 Share Posted April 2, 2004 Originally posted by meldorian: Still, it is rather amazing that the US standard AP round is better than the Russian one. The Russian one is not only heavier, according to the data in CMBB it also has a slightly higher muzzle velocity. I would certainly expect it to penetrate better than the 76mm AP round, just because its kinetic energy should be somewhat higher. Russian 85mm APBC does out penetrate US 76mm APCBC, at least in the data given by rexford above. However, all AP shells are not created equal. Note that the 76mm shell is capped whereas the 85mm projectile only has a ballistic cap. This means that the 76mm shell would be more effective against face-hardened armour. Other things like shell quality and sharpness of the nose comes into play as well. 0 Quote Link to comment Share on other sites More sharing options...
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