I recently traded my first revolver for my second. I just fired about 25 rounds out of it and it now has pronounced rings on the barrel-end of the cylinder where the cylinder meets the forcing cone. This revolver has a matte-finished cylinder. My last one had a stainless finished cylinder with the same issue. After attempting to clean with nitro-solvent and CLP, I still cannot get the rings out. Any suggestions would be greatly appreciated!