This is now my 40th hunting season and for many years I worked in the wilderness, solo, for periods of 3-5.5 months throughout B.C., most of northern Alberta, some of the NWT and I have been in Alaska. I have had about 60 situations with Grizzlies and have been within 10 yds. of them, both armed and unarmed.
The situation I refered to was mid. Oct. 1979, on the WhiteSwan Forest Rd. in the East Kootenays of B.C. and I was loaded with 175 gr. PowerPoints in my pair of Ruger M-77 Mags. I was only using these because my .338 had feeding problems, another story.
I have seen Grizzlies shot with the 7 Mag., the .270 Win., the .338, the .300 mags., the .30-06 and so on. The person I know who has shot the most Grizzlies is a head guide for Big Nine Outfitters in north-eastern B.C., he had shot 51 Grizzlies when I met him in Sept. 03-this is NOT B.S., he has photos of ALL of them.
This chap uses a Mauser based custom .35 WAI and he was quite dismissive of my comments about seeing bears killed with the '06. He is 10 yrs. younger than I and although I have a great deal of wilderness experience, he has more than I do. So, I tend to take his opinions as a pretty fair basis on which to compare cartridges.
I very much prefer to us a larger bore, although the 7mm Mag. will certainly kill Grizzlies and I prefer heavy, controlled-expansion bullets, as well. I usually hunt solo and frequently in very remote fly-in areas, where, if I am injured the possiblity of air medevac is chancey. So, I feel safer with my .338 Win. or my .375H&H than I would with a smaller bore. I guess everyone has to determine what works best for him and years of experience hopefully help one to do so.
I have noticed, though, that more and more B.C. hunters are going to the larger bores and I suspect that the Grizzly problem has something to do with that. If attacked, you will be lucky to get ONE shot into an oncoming Grizzly, I just think that a .338-250 gr. is more likely to shut him down than a .284-175 gr., but, maybe I'm wrong, I try to avoid bears when hunting as they always swipe a person's meat......they are sorta like politicians, they just take!