Both are good, I have a 300 WSM in a Ruger M77 and it is very accurate. ammo is not cheap and you will not be able to find it as easy as 300 WM. If you handload the WM will give you higher velocities. The WSM will limit your COL to the length of the magazine well and with the heavier bullets it will take up some of your case capacity.Both are good, I would say get the one that fits the best. You will probably want to put a sims recoil pad on it also.