I have been really impressed with Hoppe's Black High-Performance Copper Cleaner.Just used it on a new barrel during break-in and between groups,followed by a regular solvent.After 75 rounds,I still don't see any copper residue in the barrel.I apply it to a patch wrapped around a loose fitting bore brush.I used it on some other barrels that had been cleaned,but still showing a little copper,a couple of patches and that copper was gone.It says it's safe on any barrel