I prefer it with the flat ammo clip now, I thought the round one looked a bit uncomfortable.
The only bit I'd be concearned about is the top - the carry-handle thing looks a bit heavy duty when it could be a lot thinner, more like machined plate than solid steel. It'll sorta hide the 2 bolt part under the handle as well when in a FPS view - which would be a shame as it kinda detracts from the model overal, like with gun models any detail like that which isn't visible is a waste that you should certainly try to avoid.
Has it got any moving parts? - like the hand rest thing could act like a shotgun handle, heck you could make the bottom barrel shoot shells as an alternate fire - that would be cool. Moving parts on a gun really help with player immersion, especially along with animated hands.
Van-B
Put those fiery biscuits away!