They are capable of firing two shots in very rapid succession, but will then require a time-consuming reload. In general the entire barrel is hinged to the stock and the cartridges are changed at the base of the barrel while the gun is in the open position.
The double-barreled shotgun is therefore an excellent tool for many hunting, pest control or home defense applications, but may be less useful for police force or military applications.
An "over and under" shotgun is a type of double barreled shotgun in which the barrels sit one on top of the other. Contrast with the "side by side" shotgun, in which the two barrels lie beside each other. The latter is the most classic archetypical image of what a shotgun should look like. "Over and under" shotguns often have only one trigger, which fires the two barrels successively. They are often used for sporting competitons such as trap shooting or skeet, since for those sports the barrels' difference in elevation is considered less of a problem than the difference in windage from side-by-side shotguns. Elaborately decorated, precision engineered over-and-under guns are among the most expensive of all firearms, and were once a traditional present to statesmen.
"Sawn off shotguns" are usually made from double barreled shotguns. Unlike tube magazine shotguns (such as pump action or semiautomatic varieties), the double barrelled shotgun has no mechanism forward of the breech, so sawing off much of the barrel does not prevent it from operating. Consequently, criminals who desire a more readily concealed firearm may saw off much of the barrels, and perhaps also the stock, to shorten the gun. The resulting weapon is much less powerful and quite inaccurate. Modifying a shotgun in this way is illegal in most jurisdictions.
A related but rarer concept is a "drilling", a firearm constructed with three barrels: usually two shotgun barrels, and a single shot rifle barrel beneath them. This arrangement allows a hunter to hunt small game or fowl with a double-barrelled shotgun, but have a rifle shot instantly available if a longer range shot, or heavier game, is encountered. Drillings are mainly encountered in Central Europe.
See also: gun