[Marcello]

"The crew was reduced from 5 to 4 in the rusian model T-34 M1947 because was use new radio device and this tank don't need a special crew member for maintence the radio. So this bug is not only in Czech OOB but in all oobs. I think all T-34 produced after 1947 should have 4 people crew."

The thing is, wouldn't the BMG become useless as soon as you switched to a 4 men crew? After all it is a conventional ball mount, not a driver operated fixed MG. And if so, why keeping the mount in new production tanks ?
It looks like something that could be easily omitted, saving resources and strenghtening the glacis plate, instead of being a modification requiring a substantial redesign.