When I clean my 300 wby barrel and use Hoppe's #9 copper remover I think I have my barrel clean but I decide to use a brass brush with the #9 and I get more black out, no blue color. I decide to use Montana x-treme Copper killer 50BMG special formula using a brass brush and I continue to get blue. Is this blue copper or is it blue coming of this brass brush caused by Montana x-treme. In other words is it possible to continue to get blue off the brass brush caused by this Montana x-treme or does this blue continue to be more copper, thanks