3 years ago I would have said 300 Win Mag. Today? 300 PRC. It's a "new and improved" 300 WM. I was also after a bigger, longer, more ballistically efficient, hard hitting caliber and ended up deciding on 300 PRC. Its a real pain to find ammo for it right now but it's out there and seems to be available in waves. So when you find some anywhere buy as much as you would reasonably need because when its gone it will be a while before its back again.