At first blush, it sounds like this researcher knew what his result was before he started his research.
As a practical matter, killing a bear with a gun before he can kill you is a very tricky proposition. A head shot will just piss him off.
In any case, this is not the “bear” mentioned in the Second Amendment.
There is no problem even driving a 357 mag and above bullet through a bears skull. I have done it several times.
This guy is a pro bear anti who is more concerned about the bears then people.