What if you whack your scope on something? Very simple situation - you don' t find out something' s wrong until after the shot. Yes, you can put a bullet in a 2-3 inch circle at that range, but if something goes wrong, you go from a perfectly lethal shot to tracking a wounded deer across five states. You do the same thing with a lung shot, and the bullet hits: the spine (up), the heart (down), the front shoulder (to one side), or the liver (the other side). MUCH better odds of a clean kill.

Check out one of the big sites, a magazine, or a book. You can find plenty of diagrams of where the spine sits in the neck. Please avoid using the shot whenever possible, though.