A year ago I decided to get a Ruger 77 MKII in 300 WSM, and I love it. It will put my 180gr and 150gr handloads in a .5" group at 100 yards. If you are going to use 180gr or less most of the time I would say go with the WSM. If you want it for the heavy bullets over 180gr the WM will have a bit more case capacity and faster velocities. I went with the WSM because I wanted a short action magnum with no belt and a 180gr X bullet will kill anything in North America and then some.