The short recoil action developed for the M1911 has been widely copied by hundreds of subsequent firearms, becoming the operating system used by almost all modern handguns. The single-action operation of the weapon allows for great accuracy due to a very clean and crisp trigger action. A large aftermarket exists for the M1911, providing improved grip safeties, grip panels, match-grade trigger units, adjustable target sights, accurized barrels, night sights, improved magazines and many other upgrades to the basic pistol.
The M1911 fires .45 ACP calibre rounds specially designed for the weapon, now one of the most common of all pistol cartridges. The single stack magazine limits the M1911 to 7 rounds of .45 ACP, but provides the weapon with a remarkably thin, flat profile that aids in concealment.