I have seen no reason to use it at all. My PD shooting partner swears by it and we shoot the same rifles in .220 Swift. I don't use moly in mine. Mine shoots just as good as his, shoots the same amount of rounds before cleaning, and have seen no difference in wear. I do see that after cleaning I don't have to waste rounds to season my barrel to get it back to shooting well and I don't have to use a different cleaning method for the moly. Also, I don't have to pay extra for moly bullets or go through the mess and time to moly my own. Just my opinion.