your Uzi's silencer has way too many polygons, i can tell because i dont see any smoothing groups. It must have 30-40 sides!
Smoothing groups are your friend.
The wood box texture isnt really believable. You need to make it boarded and add more shadows and light. Your barrel texture is looking good, but here is what i would do to it, add contrast, and put some rust behind those spots.
Also the Uzi render is hard to see, too much contrast and not enough shown.
And after Aaaalllll of my criticism, it looks pretty good
maybe Chamfer the uzi a bit more. And then learn about smoothing groups, or skip smoothing groups and go straight to high poly(not recommended).