Cowboy style matches, so they did away with the "self start" division of said matches, and made everybody include their reaction times as part of the draw.
What Bob and others would do was, adjust the start button, on its 3 legged stand, to the point where they could draw and gun, and their trigger finger was still holding down the start button. So all that got timed was the trigger pull and hammer fall. An "honest shot" with self start blanks (not hitting anything, obviously) was .06 of a second. Bob's cheating method was turning in times of .02" second.