5000+ rounds of Wolf and Barnaul, not a single problem as of yet. She gets a good clean after each lead session, and to be honest It isn't anymore difficult to clean than when I run brass. Chrome lining in the chamber and bore is key here, it cleans up without any extra effort. Hose the chamber, bore and bolt w/ CLP, let it sit for a minute or two and wipe until clean. I've put more than 1000rds Barnaul in a single sitting with only 3 FTF, and that was ammo related. IMO, a good AR will eat anything.