The problem when using a media for testing is that its way to easy to get the angle of inpact right.
It would be fun to see anyone putting some 50mm of hardboard or similar in an steep angle infront of the media to simulate the forehead of an animal. Then it would probably be easy to see what caliber that would keep penetrating into the media and what would deflect out from the media.

Nowdays with a lot of great bullets avaiable there would be less and less difference between calibers and velocities than in the old days when they wrote their books, wouldnt it?