>Detachable shoulder stocks for pistols date back as early as the 17th century, but the idea was revived in the early 20th century and was applied to many self-loading pistols of the day. A particularly fashionable idea was the combined holster-stock, in which the stock was hollowed with a hinged door in the rear that, when opened, created a rudimentary storage compartment for the pistol. Pistol-carbines of this type were commonly purchased by military officers at the turn of the century, and were often used during World War I. They were also a popular self-defence weapon for pilots and their observers in the early days of aerial battles, before machine guns were fitted to planes. By World War II, this concept had largely fallen out of favor due to the introduction of the submachine gun, which rendered pistol-carbines basically obsolete.
>The FN M1903 pistol, a very popular gun in its day, was built with a special set of hollow grooves in the bottom of the butt, into which the machined section of the stock was slotted. With the stock attached, the magazine well was extended and could not take the standard 7-round magazine, so a longer 10-round mag was developed specifically for this application.