Hyack Hyack:
My point was that there is aboslutely nothing that we can base our judgement on, other than what's used in the theater. I also was going to list them but I couldn't find the current USSR MMG that uses the 7.62x54 round.
Based on this picture, this could have been 303 Btitish,7.62x64 or (my favorite joke caliber) 416 Rigby.
.. although it could have been a civil war volly gun..

$1:
I think its faked...
But just for fun why dont we throw the VSK-94 into the ring
Wimp. That's a rifle. We're talking calibers here.