I don't have the WSM, but my good buddy has had excellent luck with Magpro in his rifle using 130gr Scirocco's. He is deep into the 3300 range in a 26" barrel. Very awesome accuracy. I am shooting the 264WM and using Retumbo with 140gr AB's. I am getting mid 3100's without issues. That 6.5WSM is an awesome cartridge. Wanted to build one when I found a decent deal on my 264. Scotty