re: "his primary carry weapon was a six shot .22 LR revolver"
Not a good idea, IMO. Head shots with a .22LR? There have been more than a few cases where the .22 round either penetrated the scalp and circled the head outside the skull, or did the same thing inside the skull without stopping the shootee. Imagine a triangle with the point above and between the eyebrows, and the base along the top lip with the sides bisecting the eyes. The round, in an effective caliber, needs to penetrate that area of the brain housing unit, to effectively turn the power off (presuming a frontal shot). The skull is a hard target, and the brain in a moving head is a small one.
Good luck relying on that idea! I'll go for 2+ shots center-of-mass, and then if that fails, go to the head or pelvis what's the pelvic version of a Mozambique? the Mozamdique?!). Shoot till the threat is over.