When I shoot my S&W 686, I seem to get a black residue on the front of the cylinder and a little on the sides also. I shoot 100 or 150 rounds 143gr fmj's. Is that a lot of shooting? Do you guys have any suggestions to clean that black stuff off. Especally the front of the cylinder. There seem to be ridges from the machineing and cleaning in these ridges is troublesome.