I would blend the different colours on the camo a little more (a minor blur might do it) and maybe give the metal some specularity (glossyness) and possibly some reflection depending on the finish.
Also, the Butt of you're gun looks pretty flat, maybe clicking on the smooth button in the Polygon shelf might help?
"When you are born, you have a resposiblilty to program you're own mind, if you do not accept this responsiblilty, then the world will do it for you"
Aol Instant messenger: mrcoolbp2