A couple come to mind, both from Texas. In the Texas Tower massacre in 1966 in Austin, it was rifle fire from armed citizens on the ground that pinned psycho killer Charles Whitman down and stopped the killing until another armed citizen who knew the building led two Austin cops to the top of the tower, where they killed the SOB. In the other case, a man whose name was never made public -- known only as "the hunter" to the press -- pulled over, took out his hunting rifle, and killed a man who had just murdered a Texas highway patrol officer. Both distances were three-digit yardages.
If "within the totality of the circumstances" the guy needs to be shot, the distance is easily explainable in court.