Granted I'm not an expert on the subject, but I recently watched an episode of "Modern Marvels" which addressed shooters, and they presented a man who they said was a world champion quick shooter. I'm sorry but I don't recall his name.
He showed and specifically discussed how he can draw and shoot six shots from a single action revolver faster than a double action revolver, because the human thumb is a more efficient cocking mechanism than the inner workings of a double action revolver. I'm basing my statement on that show, and my knowledge ends there.
Jerry Miculek fired a record six shots, reload and another six shots just under three seconds with a revolver. The prior record holder with a double action revolver was Ed McGiven.