I've noticed on several of my revolvers (bead blasted finish) that I can't seem to get the powder off the gun around the forcing cone and at the edges of the cylinder between flutes. The powder is so baked on that even my bottle of hoppes powder solvent only removes it about 70% of the way. My 66 combat magnum has what seems like permanent powder burns. there has to be a better powder solvent than the hoppes I'm using.