After swabbing with solvent to get rid of lighter oils/grease, I used JB paste just because I had some on hand. Seemed to work very well, but some of the other recommendations are probably at least as good. Whether it had anything to with using the JB, the time of day, the phase of the moon, or blind luck, my "shoot in" period was very short for my 54. It seemed to settle down and really shoot consistenly after only a few rounds.