T34 76.2mm APBC vs Tiger II Side Armor

[rexford]

There are two firing trial results floating around the grog community, one where 76.2mm APBC is a total failure against Tiger II side armor and another where it succeeds at 300m.

The results can be explained by examination of penetration estimates for typical and special heat treatment 76.2mm ammo.

Working from the U.S. firing trials with 122mm APBC, 76.2mm APBC (BR-350B) would penetrate 76mm homogeneous armor on half the hits at 300m. Now that's a mouthful.

The side armor on Tiger II would present 86mm resistance to 76.2mm APBC hits on turret side, and 89mm when rounds struck the hull superstructure side.

76mm penetration at 300m against 86mm and 89mm effective resistance will succeed on about 5% of the hits, at best. So firing tests with 76.2mm APBC would be expected to fail against the Tiger II side at 300m, as they did.

Now, Miles Krogfus' article indicates that the Russians specially heat treated a small percentage of the 76.2mm APBC rounds, and the increased penetration would be about 10% (working from the constants in Miles Krogfus' article).

So special 76.2mm APBC would penetrate 84mm at 300m, which is enough to defeat the 80mm at 20 degrees from vertical side plates on almost half the hits. Against 80mm at 25 degrees from vertical, 84mm penetration would succeed on 20% of the strikes, which is the Russian IP criteria (Initial Penetration).

The inconsistencies in the firing test results against the side plates on Tiger II can be explained given assumptions that are consistent with information provided by Miles Krogfus in his article.