I've heard that jaw thing before.A calm deer that reacts to a shot ducks. You are aiming for the ear when you shoot at head. This is 2 inches above jaw. You'll miss high. If you miss low you have no business shooting that shot. I don't promote head shots; lungs are too easy to hit. But....... I have shot 2 does in head. 1 bow, 1 12 gauge. Neither knew what hit them.