An easy one. If you get it wrong you must immediately shoot yourself in the head.

Callahan: "I know what you're thinking, did he fire only 5 shots or was it 6, well in all the confusion I don't remember myself. But this being a 357 magnum, the most powerful handgun in the world and would blow your head clean off. You have ask yourself something, do you feel lucky, WELL DO YA PUNK?"