A shotgun is a weapon that is typically used to fire multiple projectiles in one shot. Many types of ammunition exist for the shotgun, such as slugs (single projectile) and shot (multiple small caliber projectiles).
There are many different actions used in shotguns, with break, pump and semi-auto being the most common. Break action shotguns are normally hand fed creating the need form the user to eject the spent shell and place a new one in its place. Pump action typically feeds from a internal tube magazine under the barrel, as do most semi-auto shotguns, although some modern types used in military like the Spas 15 are equipped with a detachable box magazine holding around 6 rounds.
Some shotguns are capable of fully automatic fire.