Exactly, AK gun pressure is enough to tear almost every mbt armour in existence out there, during trials, it ripped ERA equipped undisclosed mbt! No further details can be given but gun pressure is more dependant on shell velocity and 6250 is excellent pressure by any standards.
Here is an interesting post from Methos from defence forum india that sheds more light on the subject....
Read what I wrote above in post #2092. BM-42 has large caliber fins and an overall greater diameter -> this will lead to more friction/drag -> higher loss of velocity during flight. BM-42 has a fin diameter of 125 mm, while 120 mm APFSDS have allways less than 100 mm fin diameter.
"Also as written in "Kampfpanzer Entwicklungen der Nachkriegszeit" monobloc penetrators have a higher penetration capability - DM 33 is monobloc, BM-42 uses a two-part tungsten core.
In my opinion the problem with WITU is that they base their "facts" probably at different sources. I.e. Jane's claims that DM 43 has a pressure value of 5500 bar (550 MPa), while U.S. sources attribute the same round with a chamber pressure of 5800 bar... because they probably use another base for their values. Rheinmetall stated in the old DM 63 article that DM 53/63 has a chamber pressure of 5500 bar at 15°c (the same as DM43). It has been claimed on German forums that at very hot climates (60-70°c) DM 53 is coming very close to the peak pressure of the shorter L/44 gun (7100 bar). So unless the Americans can't fire their APFSDS in hot climates (like Egypt, Afghanistan or Iraq) - which has been proven to be wrong - the U.S. use another base pressure values at least on a different situation (maybe also for velocity, but we don't know anything more detailed about it). So the 5800 bar for M829A2 in the image in post #2094 above could be practical 5500 bar at 15°c as for DM43.
One indicator that the U.S. might base their pressure values on another situation is the testing of KEW-A2 rounds in Leopard 2 tanks - there on page 14 is a graph about the performance of KEW-A2 regarding the dependency of speed on temperature: Jane's claimed that KEW-A2 has a muzzle velocity of 1,700 m/s - this is reached at ~22-23°c (~75°F) and not at 15°c! At 15°c the muzzle velocity is only ~1,675 m/s."