They look alright, though some of them appear rather blocky.... the Vintorez in particular, one pixel extra on the bottom right corner and it should work.
Also, in my opinion the Groza looks slightly odd, I can't quite place what you need - play around with it a bit....

Well it's generally hard to give them a not so blocky look when you're working on such a small scale pixelwise.

True, though these aren't very blocky... just try another pixel at the bottom left edge of the Vintorez.
*sighs* Bloody square shaped pixels T_T