How many people have actually shot a charging grizzly bear inside of 40 yards with a 6.5 CM, 7mm-08, 260 rem, etc. (or any other centerfire rifle smaller than a .30) and the bear continued to attack?
I have had multiple encounters with interior grizzly bears while hunting, and fortunately have not had to shoot any. I don't disagree that bigger is better, but a 120-140 grain bullet @ 2850+fps is going to cause some serious discomfort/damage to any animal. I'd be real interested to hear of an actual firsthand story where a good shot was made with a centerfire rifle, and the grizz kept coming as if nothing happened.
Almost every grizzly story out there where there was a bad ending, the victim either had no weapon, only had spray, or had a weapon that they were not able to use due to a variety of factors.
I know that there are hunting stories of grizz wounded at whatever distance broadside with larger calibers, that went into alders, etc. and then charged, etc., but that is not what we are talking about (Sheep hunting, and all of a sudden a bear comes at you and the first shot is made at close range, head on with a 6.5-.284 caliber). I think it is highly likely a charging grizz shot with any centerfire rifle is going to either pause in confusion and offer a follow up shot, or is going to veer off. Just the sound of a high powered rifle makes them retreat in most instances, much less excruciating pain to go along with the noise.