350 to 400 gr LFN gas checked, without crimp groove. Ask for 460 diameter and size that size as long as loaded ammo will slip into the chamber. Set OAL so it feeds smooth as water pours out of a boot, and crimp firmly enough so bullets don't get knocked deeper in the case from magazine slamming. Use a Lee factory crimp die to do the crimping. It seems most people are happiest with 400 gr. 350 gr will kill anything in North America with ease and less recoil. The gun will shoot 500 grainers very well, and deliver enough power to break both shoulders on a mouse or a moose. But a 350 gr will break one shoulder and kill him as quickly. So if I'm leaving you on the fece with this answer, email me at LBTisAccuracy@localnet.com and we'll discuss your personal preferences.