I started using Breakfree on M16s and M60s while I was in Army. When I retired in 1991, I kept using it on my personal weapons. I've always had good luck with it and have never had it gum up anything. I collect and shoot milsurp rifles and muzzleloaders and use it on all of them. I recently tried Ballistol after reading some good reviews of it on this forum. I checked my .62 Fowler a week after lubing the bore with Ballistol and found rust in it. Maybe I didn't quite get the bore dry after cleaning it warm soapy water. I used it again today after shooting my .40 North Carolina rifle. I'll check it in a couple days. If I find rust, I'm going back to Breakfree.