I have killed several Brown and Grizzlys with my 325wsm. As far as that goes I have killed quite a few with a plain ole 30-06. My go to load for my 325wsm is Reloader 17 and a 200 grain Accubond.
Get close and keep shooting until he stops moving, then shoot once more.
I have several loads for 325, so let me know what you have in mind.
Swift A-Frame load.
Game King