I find that after shooting a 1 day or 2 day handgun "gunfighting" course, my groups from a static 2 handed shooting position increase in size.
I surmise that my brain realizes just how accurate I need to be in a gunfight. Under the right conditions (essentially any day of the week) I am shooting a 1" group at 15 yards with my handguns, and placing 10/10 hits on a 8" plate at 50 yards.
I routinely put as many rounds as I can fire in the time I am given, in a thoracic cavity sized group shooting while moving in any of the eight basic directions, and at oblique angles (ie, target is not squared up to me, and I am not moving to or from the target at a perpendicular angle).
oh yeah, I also try to do that stuff with my non-dominant hand as well.