What are you trying to do by moly coating cast bullets? The reason to do jacketed bullets is to reduce the friction of bullet to bore, and make the transition into the lands easier. With lead bullets these two things aren't a problem. Moly does, however, introduce its own set of problems when used. I would think doing this is trying to solve a nonexistant problem. If you want more speed and less leading the things to look at are first and foremost the fit of the bullet to the firearm, whether it is a revolver, pistol, or rifle. Next is bore condition and next is bullet alloy and lube. If you are having a problem with leading or poor accuracy at higher velocities you will be well served to address these areas first. If you're just doing it for fun because you can, go ahead but you will likely not see any improvements.
