Not bad at all, although the grip seems to have been split along the middle and your butt seems to be missing entirely (twss). Also like Kuro said, the entire front end, foregrip and barrel, needs to be scaled along the x-axis. Ignore the silencer though, that looks fine except the thickness at the tip (twss).
I have to say though, this is your best work as far as lighting and shadows go. They shadows seem a little hard, but that can be easily remedied.