Fast Dear Tune up: "The next thing I did was worked on the crown a little. First, insert a pellet into the muzzle with the skirt facing out. Backwards if you will. Push it just past the opening. The logic here is to prevent any steel particles from getting down into the barrel. Then take a brass Phillips Head screw with a head just a little larger that the bore, being sure that the slots do not come in contact with the rifling, and chuck it into a variable speed drill. In my case, I went to the auto parts store and bought 2 grades of valve grinding compound, medium and polishing. I first used the medium grade applying a slow even pressure on the muzzle. Important; take care to keep the drill as straight as possible. I then did the same with the polishing compound. Now take a small piece of 600 grit wet/dry emery cloth and make it into a cone small enough to insert into the muzzle. It needs only go in a short distance, and then twist it back and forth lightly to clean off any edges. Now to check for any burring that may be present, take a Q-Tip and insert it into the barrel and withdraw it. If you "