...Just kidding.
Pretty nice looking, i like the metal effect you achieved on the gun, and the can also looks very nice, lots of detail on a small space.
I'd elongate the back of the gun more, stretch it back some, everything from the trigger (including it) to the back would go left about 5-10 pixels. Also, the handle looks very small. On the tip, i'd move away from the black outlines, and use just a small rectangle and some suggestion of a hole (a light grey or something). Check my edit for an idea.
Also, not sure if you're heading somewhere with this, but the composition looks odd. I'd center it vertically, and place it to the left of an image being sprayed on the wall (maybe a stencil i dunno)