I have both the Montana extreme copper killer and the Bore Tech CU +2 copper remover. I may have to run me a test. I don't use the Montana Extreme anymore, I can't stand the ammonia and I'd rather not put it in my barrel if I don't have to. I've been using the B.T. copper remover for several years and after treatment per directions it does it's job by verifying with my borescope.










