I've noticed that, when firing the PPSh-41, the soldier's left hand is holding onto...nothing, and his right hand isn't really positioned properly, either. It's as if the MP40 animation was re-used for this weapon.
It sure would look better if he was holding onto the drum (as seen in the image below) or the portion of the stock just in front of the trigger guard. And, of course, it would look much better if his right hand was farther back: