I totally agree with sigma's crits if I"m being as picky as I would be with my own work. Aesthetics and function are really closely tied with weapons, esp if you're basing work off of real world guns.
But you prefaced the fact that you're not a gun gal or guy, and damn, these are just too much fun. I love the vibe you have going between the big clunky shapes that nonetheless remain free of random, unnecessary greebles. The embellishments (esp. that lettering!) are super cool, and the finish is really beautiful!
I"d just say keep going a little further to modify/disguise the original gun designs a bit further. Obviously if you don't know your stuff, the key, identifying features are gonna be harder for you to recognize, so just keep mixing and matching. =)
Great work, rock on!
Oh, the ex-shotgun is my personal fave. =)