I used to teach my lads (corrections riot squad and perimeter security teams) to shoot instinctively out to 25 yards.
About all of them could hold 6 consecutive shots inside a 6" circle at that range with the gun held shoulder height, shooting
rapid fire, DA.
This would be much more difficult to learn with single shot pistols. I would of course, say it is a distance deal, not a
barrel length deal, given the "equalizer" of sufficiently accurate gun. It has to put the ball where the barrel is pointing.