Those internet gun experts are amazing!

A 5 meter (a squish over 5 tards for those Metric impaired) from a rifle shooting a 5.56 round flying a 3K fps will be devastating and truly incapacitating one inch up or down. The bigger the rifle caliber, the bigger the skull canoe will be achieved.

I believe the poster simply ignored the transference of energy from the round into the body and the hydrodynamics that come with it and probably believes that bullet wounds are perfect cylindrical little holes like cut with a laser with no effect on the surrounding tissue and organs.

Top of my head (pun intended) we have the killing of Bugsy Siegel where the head shot taken with an M1 carbine made his eyeballs pop out of his skull.