my main comment would be to attempt baking a normal map or constucting a normal using Ndo, it'll make the details really pop, obviously
and you should probably get a spec on there as soon as you can, it's really what sells metal, without it it always looks more like rock or concrete than metal.
It's looking good though, you might want to reduce the thickness of the grip, looks a tad too thick to hold, you might want to optimise the stock a tad as well, and what's the tri count? I'm not sure if that's what you mean by polys, if so good job? nice and low