Kind of a shit picture, but can anyone tell if this is just old lead? I've got a Luger that has this build up at the muzzle when I shoot it, and I have to sort of peel it off with a small punch. It only builds up on one side of the muzzle, and its on the same side that the barrel appears to have significantly weaker rifling than the other side. The bore looks like absolute ass but still shoots almost as well as any of my other pistols do.