The question is the reverse of what it should be. You should be asking how many rounds you will fire from the gun. Do you plan to shoot 100 rounds a week? 100 a month? 500 a week? Or fire part of a box and keep the gun in the bureau drawer for twenty years? And will that be light wadcutters, or standard velocity, or +P, or +P+, or super hot handloads?
Jim