You want a bone test? Here you go. A fox from last year, Marlin 17V using a 17gr Hornady Vmax. I aimed right between the eyes at 51 yards (confirmed on Google Earth). He tipped right over. His head turned right as I shot. I found him with fluids leaking from his downward facing ear. Since I couldn't locate an entry on his front side, I figured I must have got him in the ear as he turned his head. I was wrong.
At home I looked a little closer and found the entry right between the eyes. His head turning must have been from the impact. There was no exit at all, just fluid leaking from his ear.
Here is the entry while skinning.
His jaw was locked shut from the fractured skull. The skull cap appeared solid, but the lower portion was fractured bad. The inside of the roof of his mouth was caved in too. But zero damage to the fur other than the tiny entry.
