This Guns 101 article provides basic information about shotguns:
Shotguns are a versatile type of firearm that can be used for many purposes including self defense, hunting, and target shooting. The shotgun’s claim to fame is its ability to shoot multiple projectiles, rather than a single bullet, increasing the probability of a hit. Also, unlike rifles and handguns, shotguns generally do not have a rifled barrel (meaning that the projectiles fired by shotguns are not spun as they leave the barrel).
The cartridge that a shotgun fires is called a shell. The shell contains the projectile(s), a wad and shot cup that help cushion and hold the projectile(s) as they travel down the barrel, gun powder, and primer (which ignites the gun powder). Nowadays, shotgun shells are usually made of plastic, with a metal base. An example of a shotgun shell is shown below:
Shotguns come in various gauges, which is a measure of the barrel’s inside diameter. 12 gauge is the most common by far, however 10, 16, 20, 28, and other gauges are available. The smaller the gauge number, the larger the interior diameter of the shotgun’s barrel.
Shotguns are usually considered shoulder arms, meaning that the stock (the back end of the shotgun) is placed against the user’s shoulder, and the user then presses the side of their face against the side of the stock, while looking down the length of the shotgun to aim. The picture below illustrates that firing position:
There are three basic types of ammunition that shotguns can fire. These are birdshot, buckshot, and slugs.
Birdshot refers to small pellets fired by a shotgun. A birdshot shell may contain hundreds of pellets, and is suitable for hunting birds, as well as shotgun sports such as trapshooting and skeet. Birdshot is not suitable for use on larger game or for self defense.
Buckshot refers to large pellets fired by a shotgun. A buckshot shell may contain about 10 pellets, and is suitable for self defense and hunting roughly deer-sized game.
A Slug is a single large projectile fired by a shotgun. Slugs are similar to rifle or handgun bullets, but are generally larger. Slugs are suitable for target practice, hunting deer-sized and larger game, and self defense (although buckshot may be a better choice for self defense purposes).
A chart showing the size of various birdshot and buckshot pellets can be seen here.
Types of shotguns
There are three basic types of shotguns: semiautomatic, pump action, and break open.
Semiautomatic shotguns fire one shell each time the user pulls the trigger. Once the shotgun is loaded, the user need not do anything other than pull the trigger for the shotgun to fire each shot, until it runs out of ammunition. These shotguns use some of the energy from the previously fired shot to eject the spent shell and load the next shell. Semiautomatic shotguns allow for a faster rate of fire than either pump action or break open shotguns, and generally have less recoil. However they are more complex and therefore less reliable. An example of a semiautomatic shotgun is the Remington 11-87.
Pump action shotguns (such as the one pictured above) require that the user “pump” the slide (the forward corncob portion where the non-trigger-hand rests) to eject the spent shell and load a fresh shell. Such shotguns are mechanically simpler than semiautomatic shotguns, yet allow for nearly the same rate of fire in the hands of a skilled user. I prefer pump action shotguns when it comes to home defense. An example of a pump action shotgun is the Remington 870.
Break open shotguns hold one shell (or 2 shells for a double barreled shotgun) at a time, and the user “breaks open” the shotgun to manually load and unload shells, by pushing a lever. Break open shotgun are about as mechanically simple as can be. On the negative side, they are relatively slow to reload, and therefore not recommended for self defense. However, they are great for trapshooting and other shooting sports. An example of a break open shotgun is the Browning BT-99.
Shotguns, like all firearms, vary greatly in price. An inexpensive (but still good) shotgun such as the Mossberg 500 can be purchased new for around $300. An excellent specialty shotgun such as the Browning BT-99 can cost over $1,500, and this author has seen some (rarer) shotguns that cost over $10,000. That said, a more expensive shotgun isn’t necessarily better, and the key is to buy the shotgun that meets your needs.
Shotgun ammunition also varies widely in price. Birdshot is generally the least expensive, with buckshot costing more, and slugs costing still more. Some specialty slugs can cost as must as several dollars a shot.