My Kimber Montana Loves 65.0 H4350 for 1/2 to 3/4 in. groups @ 3050 fps. Not super fast but a +P 30-06.
I think the 300 WSM is more than a +P 30-06, especially with RL17... loaded with that powder, it equals the average 300 WM.
But I "get" what you're referring too. IMO/E, the 300 WSM is a solid 150 - 250 fps ahead of the 30-06 depending on powders used.