IMO none would be perfect they would all have give and takes associated with a range from Mule deer to Griz as you indicated. That said if Grizzly where on my radar screen the min I would take personally would be 338 wm. So if your serious about hunting grizzly's in the near future that would be my suggestion go big and tailor it to your needs for the smaller stuff. However if your wanting a rifle thinking the biggest animal you may hunt is a Grizzly, then the 300's will serve you well until its time to go after them big bears.