so russian APHE rounds such as the 85MM on the T34 85 have flat heads causing the rounds to normalize with the angled armor of tanks allowing them to pen better on angles which is historically accurate but it overperforms by a lot in game.
for example in protection analysis the american 90mm of the M26 pointed at the Panthers front plate says 180mms of armor roughly
but with the russian 122mm on first 6.3 IS-2 or IS2 1944 with the BR 471B which it shows a different value which is 130mm of armor allowing it to pen the panther at any range and you cannot angle it
the downsides of a flat head round are that it reduces effectiveness on flat armor like for example a tiger 1 or a ARL 44s manlet which this downside is not modeled either
i propose you simple nerf the angle performance of the rounds and fix the 1944s insane volumetric armor and you can drop the IS2 and IS2 1944 as neither the IS-2 1944 or IS-2 is a match for the T26E5 or E1 or literally any other heavy
At least on the 80mm it doesnt overmatch it, on the side it does to some extent, it doesnt completely overmatch it but it does reduces the ricochet angle