Boomer is exactly right. The only guaranteed shot to anchor any animal, is one that severs the spine or hits the brain.
In 2010, I shot a big black bear, at the pointblank distance of 28 paces. This bear was walking up the trail toward me, and was basically unawares of my presence.
I hit him with a chest shot, inside of the right shoulder, with a 400gr Hornady IB, from my .416RM. The bear reacted to the shot (as
Gatehouse said), by running away. But he covered 80 yards before expiring.
So if he had been interested in attacking me, he certainly had enough energy left to reach me. And even with the huge impact of that 400gr slug, he did not go down, and the speed he moved at running away was remarkable.
The blood trail was very easy to follow!
The heart was grenaded...
I'll still always take a firearm over bear spray...