Multiple-barrel firearm
These firearms were limited in firepower by the number of barrels bundled, and needed to be manually prepared, ignited, and reloaded after each firing.
Alexander Forsyth's patent of 1807 (which ran until 1821), and the Industrial Revolution allowed pepperbox revolvers to be mass-produced, making them more affordable than the early handmade guns previously only seen in possessions of the rich.
Samuel Colt owned a revolving three-barrel matchlock musket from British India,[5] and an eight-barrel pepperbox shotgun was designed in 1967, but never went into production.
Modern derringer designs are almost all multi-barrelled, most variants have two-barrels or four-barrels, thus essentially makes them a compact and concealable handheld version of the volley gun.
The COP 357 is a .357 Magnum-caliber four-barrel (side-by-side and over-and-under), double-action hammerless derringer introduced in 1984, and not much larger than a .25 ACP semi-automatic pistol.
[11][better source needed] The name comes from the double tap shooting technique, in which two consecutive shots are quickly fired at the same target before engaging the next one.
These first double-barrelled weapons were black powder, smoothbore muzzleloaders built with either flintlock or percussion cap ignition systems.
Many gunmakers tried various methods to rectify this problem, all to little avail until Westley Richards invented the "Dolls head" lock in 1862 which greatly improved rigidity, this was followed by James Purdey's under-locking mechanism in 1863 and W.W. Greener's "Wedge fast" system in 1873, finally the basic break open action known to this day had the strength required to meet the stresses of large-bore projectiles.
It was not until the 1980s and 1990s, with the emergence of the big game hunting industry in Southern Africa that the production of double rifles resumed at a steady rate, driven largely by demand from American sportsmen.
The Gatling gun's operation centered on a pepperbox-like multi-barrel assembly whose design facilitated better cooling and synchronized the firing-reloading sequence.
This cyclic configuration overlapped the operation of the barrel-action groups, and allowed higher rates of fire to be achieved without each barrel overheating.
[19] None of these German guns went into production during the war, although a competing Siemens prototype (possibly using a different action) which was tried on the Western Front scored a victory in aerial combat.
[20] In the 1960s, the United States Armed Forces began exploring modern variants of the electric-powered, rotating barrel Gatling-style weapons for use in the Vietnam War.
Although helicopters had mounted single-barrel machine guns, using them to repel attackers hidden in the dense jungle foliage often led to barrels quickly overheating or the action jamming.
[21][22] In order to develop a weapon with a more reliable, higher rate of fire, General Electric designers scaled down the rotating-barrel 20 mm M61 Vulcan rotary cannon for the 7.62×51mm NATO ammunition.
