[Marcello]

Giving a look at the russian OOB, I see the problem. Probably to save the scarce weapons slots T-34s have been armed with antitank guns. Works ok with the D-44,not so great with the D-48.The only solution of sort without adding an additional weapon would be giving the D-44 BK-2/M HEAT values, issue HEAT only later (say late 60's onwards) to give it improved firepower.

Admittedly there is not a great deal online on the D-48, and what little there is is probably based on the same Jane's reference. I could try to give a look at the ordnace databases to see if I can get a look at D-48 ammo, but it is a bit elusive.