I do enjoy this gun, to be honest. Personally I think it could use a bit of blending but as is I'd give it a.... 4 out 5.
Now this I like, and much prefer to your 'theme' and 'brony' guns. The colors here are used as accents, not as primary color of the gun. The dark red works quite well with the gray hue of the rest of the gun, though next time I would recommend you pick a slightly lighter shade of both gray and dark red. Just makes the gun pop a little more I think.