This is an interesting video. I need me a shot timer, and I have to see if my single action revolver can beat my semi-automatics 
View: https://www.youtube.com/watch?v=ou_susouj7Y
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One of the things I've read attributed to Wyatt Earp was it isn't the first shot in a gunfight that matters, it is the first accurate shot.As mentioned, I have read about Wild Bill always taking careful AIM.
Hitting the target is way more important than sending bullets down range in a hurry!
Of course if you can do both great but most of us should stick with careful aiming....
He referred to a local guy, John Newman, as being especially talented with the slip guns. I recall that from Sixguns.I used to do it with my trusty Mattel "Fanner 50's." I could hit the wall every time with those plastic bullets...until I lost them all.
It's been a while since I read his book, but I seem to remember Elmer Keith talking about fanning as a serious technique. He also spoke of modifying the gun, changing the hammer, removing the trigger and such. He called them "slip guns."