Just took out my new rifle recently and noticed when I took it apart to clean it the sides of the gas piston seem to be discolored, almost like there was excessive heat that was applied to that portion of the piston. The area of the piston that is discolored is the bottom portion near were it starts to flare back towards the back of the rifle. Is that normal for shooting a couple hundred rounds with a brand new gun? There is also a build up of residue (kind of like little bumps) on the concave portion of the piston that I can not clean off with a nylon brush and solvent. Is it safe to use a br
