It would be used mostly for whitetail, but I would lke to be able to go bigger game hunting when I get older. 300 RUM doesn't seem nearly as popular and I haven't seen ammo for it or SAUM. I would most likely use 150-180 grain, since I'm not doing in moose or elk hunting in the near future. Browning and Winchester advertise that WSM has the advantage in these weights but from what I've heard maybe that isn't fully true. The less recoil and weight on the WSM's sounds good, but being lighter, they might kick the same.