I use the foaming bore cleaner, and have found it to be a very effective copper remover, but, I use Hoppe's No. 9 to get out the really heavy powder fouling deposits. Also, you will always get black patches, because, there are microscopic scratches in the bore, that get fouling in them, and you never get the fouling out of there. You need a bore light to check down the barrel, to make sure all of the fouling is out.I also do not like to use ss brushes, I use phosphour of nylon. Hope this helps.