A shotgun is an individual weapon used for warfare, hunting, or target shooting. At one end is a muzzle from which the projectile is launched, and the mechanical components are encased in a stock that lends itself to operating the rifle with the butt, or end of the stock, pressed against the firer's shoulder. Usually with considerably less accuracy, shotguns can be fired "from the hip", which often means held loosely at waist level, without strongly bracing the butt against one's body.
As opposed to a rifle, the barrel is smooth, without grooves to impart stabilizing spin to the projectile. This is desirable because the basic ammunition for shotguns does not fire a single projectile, but multiple, usually spherical, shot. Shot spread out to give a greater chance of hitting the target.
The muzzle may be flared or otherwise shaped to spread the shot in a desired pattern; the design of this function is called a choke.
It is possible to fire single bullets, usually called slugs. Slugs, which are large, heavy and slow when compared to rifle bullets, are used in some kinds of hunting; an advantage is that their range is much shorter than that of rifle bullets, and are less likely to hit beyond the target. Slugs, sometimes especially constructed (e.g., of densely compacted metal powder) are used in military and police applications for breaking down door hinges.
Shotguns can be manual, autoloading, semi-automatic, or, rarely full-automatic. Manual shotguns must have each round of ammunition loaded before firing, and the empty cartridge case manually removed. A number of sporting shotguns are double-barreled, having two side-by-side manual mechanisms on a single stock.
An autoloading rifle does have a magazine that holds multiple cartridges, but it is necessary to manipulate a lever or bolt to eject a fired round and load the next; a pump shotgun has a lever that slides in parallel to the barrel for reloading. In contrast, semi-automatic shotguns eject, load, and fire with only a trigger action.