A very interesting article is available on the NRA Sporting Sports USA website. There are some relevant historical details about the development of pistol technique in it.
U.S. Cavalry troops were required to shoot dismounted on the Army Target “L”. Even though they carried sabers and carbines, revolvers and pistols were the primary arms of the cavalry. Just as foretop men aloft in the rigging during the days of sail was [sic] admonished, “One hand for yourself and one for the ship,” so it was with the cavalryman, one hand for the horse and one for the pistol and that is why conventional pistol shooting is a one handed affair. After qualifying on foot, troops were required to repeat the course of fire while on their horse.
The Army Target “L” was pretty big, six feet tall and four feet wide. A five-inch aiming black, worth ten points was surrounded by seven concentric circles at intervals of 8.5 inches, 12 inches, 15.5 inches, 19 inches, 22.5 inches, 26 inches, and 46 inches and of descending value nine through three points. Any hits on the remainder of the frame were worth two points. On the left side were large numbers, five through two, from top to bottom, and six through nine on the right for scoring purposes.
The influence of the US Army Cavalry on the use of the handgun in our country cannot be underestimated, although mostly forgotten a century later. The Cavalry was the branch of the Army that led the development effort for the 1911 pistol. Cavalry doctrine of that time is the reason the 1911 has a spur hammer, manual safety, and grip safety. Those are details for another time, though. Teaser: the 1911 was NOT designed to be carried ‘cocked and locked,’ contrary to popular opinion.