The .270 WSM is plenty. I killed my moose with a 30-06..200 grain Nosler Partitions. Two others in camp when I was there came with a pair of .308's loaded with 150 grains (not sure what make). The guides were not happy as they were told to bring nothing smaller than a 30-06, but both hunters killed their bull with the .308's and they didn't travel very far.