"Physics says the .338WM has to come back harder in equal rifles."
Yup, hard to argue with that one...
Stock design is huge in handling recoil...
I agree 100% and when I owned a .338WM it was for about two weeks. But found I could shoot a .300WM with no problem at all. The stock on the .300 at the time was the B&C Medalist which IMO helps with recoil very well.
CLB