Thats a very big skull.
No bigger than any other. That's what you call skill and training. Hitting a small target from a long ways away is what being a sniper is all about.
Good hunters do this as well. Plinking groundhogs from 500 or more yards away on a nice sunny Sunday afternoon is practice, and a lot of fun.
A well trained military sniper can make that groundhog 'hop' from 2 miles away.
The way the quote reads, there is hundreds of yards of penetration, ergo the big skull comment.
All you say is true but......
Most skulls only let you shoot a bullet into them perhaps a foot at most before the bullet comes out the other side.
This bullet went hundreds of yards into the skull..........
Yes I know what the author meant but it sure sounded odd.