I've used it in all my rifles for well over 10 years and have had zero problems with it...my target 6PPC has almost 2000 rounds in it and I had the bore scoped last fall and it looks as good as new, no spider cracking in the throat or anything..I will never shoot anything but moly or danzac coated bullets..they cure all Barnes X-bullet fouling problems in my hunting rifles, I've never let one sit for long and clean them all the time and have never had any rust problems or any other thing wrong, everyone get excited about all the black that just never leaves the patch, that's right, it's not supposed to leave..it fills in all the little marks and scratches and little nicks here and there..I can't see why so many people abandoned it so quickly...great stuff, almost as good as Danzac..