Pistoleers, the reality is that most bear encounters involve encroaching in the bear's space in heavy foliage or coming around a blind corner or stumbling on a carcass site, during which there is barely enough time to pull bear spray, let alone unsnap a holster and quick-draw a pistol. The reality is that in most cases it is the person following or nearby who sprays the bear or uses a firearm to try to stop the bear attack. You'd better make certain that your hunting pal is a proficient pistolero or bear sprayer.
The case where a bear has charged and is put down with a firearm by the person being attacked are always very questionable.
A friend once told me of hiking into archery elk hunt and hearing his partner behind exclaim, "Bear!" He looked up and saw the griz coming at him through the brush above the trail. By the time he unsnapped the holster right on his chest and began to pull his pistol, the bear had come within arm's distance and then bluff charged away below the trail. He said his pistol was about as useful as "tits on a boar! It's so quick that you'd better file the front sights off the pistol so when the griz shoves it up your behind it won't hurt so much!"