I just got an AR barrel back from having a flash hider permanently attached and they left several tool marks on the barrel that marred its finish. They're just nicks in the parkerization, I'm not real pleased about it, but I reckon that's probably just part of it. Anyhow, I'm a little OC when it comes to that sort of thing and I really want to touch up those spots with something, can in get any recommendations of what to use?