Volley gun
The Ribauldequin was a medieval version of the volley gun. It had its barrels set up in parallel. This early version was first employed during the Hundred Years' War by the army of Edward III of England, in 1339. Later on, the late Swiss army employed it.
Single-shot
The handgun began as a single-shot weapon in China in the 14th century. In its many versions it remained a muzzle-loaded weapon until the advent of the metallic cartridge in the first third of the 18th century. Such single-shot cartridge-firing pistols were short-lived, as revolver technology evolved rapidly, and cartridge conversions existed for the common models of cap and ball revolvers. Two forms of single-shot pistol, however, remained: single-shot derringers, and target pistols, which were essentially single-shot rifle actions cut down to pistol size. The Remington Rolling Block is perhaps the most well known of these. As the era of single-shot rifles faded, so did these early single-shot pistols.