I always use greased lightning (cleaner) mixed with hot water and a bronze/brass brush followed by patches. I only use a brush when I am cleaning a gun for long storage. Also that mixture works as a good patch lube while shooting at the range. Cleans your barrel as you shoot. I don't know but I don't see how a brass/bronze brush could damage your barrel unless your using a solvent that is going to react the brass or bronze. The brush alone will not damage your barrel.