Whenever anyone considers using a handgun for defense against Black Bear I suggest studying the configuration of the Black Bear skull.
The Black Bear has unique features not common to other bears. One of these is a very narrow brain case and eyesockets that have next to nothing but soft tissue behind them.
A shot head on and dead center in the eye will not come near the brain case.
To hit the brain through the eye you'd have to fire from an angle.
The most direct route to the Blacky's brain is through the nose.
Due to the highly evolved sense of smell, perhaps the most sensitive in the animal kingdom, the Blacky's entire head is adapted to facilitate that sense.
His brain sits lower in the head than other bears. Theres little but soft tissue and cartilage between his nasal cavities and his brain. Those nasal cavities are huge.