I have no experience with the WSM, but I do shoot a 300WM at elk sometimes. The WSM has a lot going for it,
particularly if you reload. Check ammo cost wsm vs wm. I get ammo for my wm for 20/box that goes into an inch and lays elk out. Std. 300wm can be found anywhere ammo is sold, IDK about the wsm.
Either one will be a great choice, and that rifle should too. Get the scope as low as possible and buy top quality rings. The scope on my 300 landed on the range bay when it broke free from the shitty rings under recoil.
It was a used ruger 77 with a cheap weaver/ring combo. I put a zeiss on with leop. steel rings and it has not moved in years.
The 300 gets left in camp most of the time anymore, pretty rare that I end up with any shots over 100, so I usually carry a 308AR or 45/70.
Motivational pics:
And coming soon to a roadside near you, CO DOWs ROBOELK>>>DO NOT ENGAGE!!!