.300 WSM. More bullets choices in .30 cal than any other, arguably the most accurate bullets are in .30 cal. WSM over the Ultra Mags because of recoil. If one wants something that most anyone can go to the range and shoot comfortably for long sessions and not worry about developing flinches over then the WSM is the choice. Ultra Mags are fantastic rounds, but too many people can't take or don't want to take that recoil.