I have never hunted grizz so take it for whats its worth, but i do have a good amount of experience with the 6.5X55 on deer. Its a great cartridge, but i had a small (150lb) buck stop a 140gr speer hot core, it didnt exit, first time for the swede, as all other bullet weights (120gr,129gr,130gr,140gr) have exited. For truly big game, moose,elk, bears i would use a 140gr TBBC or partiton.
I would use a 35 Whelen for bears, minimum 250grs and probably a 270gr NOrth Fork or 275gr Hawk. I would also imagine a broadside behind the shoulder shot would be about perfect.
as a side note, black bear hunting season has started here in N.J. a 661 lb bear was shot the first day, and thats small compared to the truly big dumpster divers.....
