I don't get any powder residue but I clean and re-lube the cylinder after about 100 rounds due to bullet lube build up. Once that lube cools & stiffens it will build up and can interfere with chambering, will also make the cylinder rotation stiffer. But . . . I do not touch the bore. If a revolver is shooting great don't fix it, leave the bore alone. It needs no brush, no oil, no patch. It needs left alone.