Years ago [before I knew any better] I cast up a mess of round balls for a ROA I had [back when they were NEW] and used some recycled .45 acp hard cast in the mix. Long shaggy dog story shortened, I must've got too much alloy in the mix, because I leaded the bore. Some elbow grease, a Bronze bore brush and some Hoppes cleaned it out, but the lesson was learned... only pure lead in cap 'n' ball revolvers, from then on.