The gun does look a little "plastic-ky" in the pics, and I can see the beginning of the seam along the barrel. Maybe something as simple as a repaint would work (after removing the seam of course...
)? I've had good success replicating gun metal by spraying the weapon flat black then working some powdered graphite over the top w/ my finger. Give a nice "blued" look to the piece. What is the gun made of?
Your airsoft collection is off the hook!! WOW!!