Swivel gun

A swivel gun (or simply swivel) is a small cannon mounted on a swiveling stand or fork which allows a very wide arc of movement. Another type of firearm referred to as a swivel gun was an early flintlock combination gun with two barrels that rotated along their axes to allow the shooter to switch between either the rifled or the smoothbore barrels.

Swivel guns should not be confused with pivot guns, which were far larger weapons mounted on a horizontal pivot, or screw guns, which are a mountain gun with a segmented barrel.

An older term for the type is peterero (alternative spellings include "paterero" and "pederero"). The name was taken from the Spanish name for the gun, pedrero, a combination of the word piedra (stone) and the suffix -ero (-er), because stone was the first type of ammunition fired.

It had a high rate of fire, as several chambers could be prepared in advance and quickly fired in succession and was especially effective in anti-personnel roles. It was used for centuries in Europe, Asia and Africa.

Although breech-loading is often considered a modern innovation which facilitated the loading of cannons, breech-loading swivel guns were invented in the 14th century, and used worldwide from the 16th century onward by numerous countries, many of them non-European. They have been called by many names, sometimes "Murderer", "Base", "Sling", "Port-Piece", "Serpentine", "Culverin", "Pierrier", "Stock Fowler", and "Patterero" in English; "Pierrier à boîte" in French; "Berço" in Portuguese; "Verso" in Spanish; "Prangi" in Turkish; "Kammerschlange" (lit. "chamber snake", properly means "breech-loading falconet") in German; "Folangji" (佛郎机, from Turkish "Prangi" or Turkic "Farangi"), "Folangji chong" (佛郎机铳, Prangi or Farangi gun), "Fo-lang-chi p'ao" (佛朗机炮 or 佛朗機砲, Portuguese cannon) in Chinese; "Bulang-kipo" ("불랑기포[佛郞機砲]") in Korean; "Furanki" (仏郎機砲, "Frankish gun") or 子砲 ("Child cannon") in Japanese; and "Bedil" or "bḍil" (ꦧꦣꦶꦭ) in Javanese. Some of them were used until the 20th century.

Swivel guns were developed and used from 1364 onward. The guns were loaded with mug-shaped chambers, in which gunpowder and projectile had been filled in advance. The chamber was then put in place, blocked with a wedge, and then fired. As the loading was made in advance and separately, breech-loading swivel guns were quick-firing guns for their time. An early description of a swivel gun puts the weight of the gun at 118 kilograms (260 lb), equipped with three chambers for rotations, each 18 kilograms (40 lb) in weight, and firing a 280 grams (9.9 oz) lead shot. The guns had a disadvantage: they leaked and lost power around the chambers, but this was compensated by the high rate of fire as multiple chambers could be prepared in advance. A swivel gun could fire either cannonballs against obstacles, or grapeshot against troops.

During the Middle Ages, breech-loading swivel guns were developed by the Europeans also partly as a cheaper alternative to the very expensive bronze cast muzzle-loading cannons, as bronze was many times more expensive than iron. As cast iron was not yet technologically feasible for the Europeans, the only possibility was to use wrought iron bars hammered together and held with hoops like barrels. With this method, a one-piece design was very difficult, and a fragmental structure, with separated chamber and barrel, was then selected.

Around 1500, Europeans learnt how to cast iron, and shifted their cannon productions to one-piece iron muzzleloaders. China started to adopt European swivel guns from 1500 onward, limiting at the same time the production of their own muzzleloaders, because of the high effectiveness of the swivel gun as an anti-personnel gun, which to them was more interesting than the sheer power of a cannonball.