They called him "Old Jack." He was a Tennessee farmer who had freed his slaves before the Emancipation Proclamation, and even had Ulysses S. Grant over for dinner one time. One of his sons had joined the Confederate army, but Old Jack was loud and clear that he wanted nothing to do with the war; told everybody he would watch from the sidelines.
Then he came home one day in 1862 and found the heads of his two youngest sons impaled on the gate posts of his house. Union soldiers from the 5th Iowa Cavalry had found the teenagers out hunting and figured they were Reb guerrillas. (They were not; they were non-partisan, like their father.) The boys were disarmed, tied to a tree, and shot. A lieutenant then decapitated the bodies and set the heads on Hinson's gate posts. Big mistake.
Jack did nothing immediately, but he quietly ordered a very special gun: a .50 caliber Kentucky Rifle with a heavy, forty-one inch, octagonal barrel. It weighed a little over eighteen pounds, and in Jack's hands was an instrument of certain, long-range death.
Moral of the story: When you see some old guy minding his own business somewhere, sitting quietly at a bus stop or something, tread lightly. You never really know what you're looking at...