A couple of clairifications. One is that he didn't state the bullet would drop 10, 15, or 20 meters, he stated that it would lose energy at longer ranges and the bullet would drop.

As for headshots, I can routinely hit a head sized target with my P239 at 15 yards, at longer distances I would want some type of rest and an optical sight. Give me a reflex sight and a good rest and 50 yards is probably the limit. However, I'll also note what can be done when shooting at paper differs greatly at what can be done in combat. In Combat I would much rather have a rifle.