i was always under the ass-umption that bore butter wouldnt foul black powder or pyrodex like regular gun oil if you dont get it out of the barrel totally. thats the only reason why i use it in my caplocks to coat the bore during the hunting season. i also use one of those air tools to blow out the charge. if i go more than 2 days hunting with the same charge i dont trust the powder anymore. that tool gets the maxi ball out but doesnt get all the powder out and you need to do a complete cleaning. theres nothing like the confidence of a fresh charge!