Apparently, aluminium, brass, and steel is so soft dirtngrit get imbedded in it easily; there are muzzle protectors out there, and i use them but before that i used to wrap the stick with a patch and hold it in the muzzle while the brush does its work. The smaller the bore the harder the muzzlepatch trick is...I never damaged a barrel with aluminum cleaning rod. Last I heard it's not as hard as steel.