Because the primer is inserted in the center of the casing base, shotgun shells are considered centerfire shotshells. These shotshells have the following parts:
Hull or casing
The casing is a plastic tube-shaped container that holds all of the shell components together. It’s also known as a shotshell. Hulls and casings come in a variety of sizes and colors.
Projectile(s) (shot pellets or slug)
Typically shotshells are loaded with multiple shot or pellets as the projectiles. The majority of cartridges loaded with shot or pellets are used for hunting upland game birds and waterfowl or for target shooting. There are a variety of different shot types available: steel, lead, bismuth, tungsten-iron and tungsten-matrix. Because lead is a toxic substance—it contaminates soils, surface and ground waters, damages habitats and can cause lead poisoning in different species—lead shot is not permitted for hunting waterfowl in North America. Please check your local regulations to ensure you are using the proper type of shot for the animal you will be hunting.
Shotshells loaded with slugs are used for white-tailed deer and other big game.
Placed between the powder and the projectiles, the wad column is made of plastic or paper and provides a seal so that the gases from the burning powder do not escape past the shot.
Powder is high-energy propellant of a specific quantity (charge) that, when ignited, creates a high pressure gas inside the cartridge case. This pressure forces the bullet or projectile down the firearm’s barrel to exit at the muzzle.
Primer is an explosive compound used to ignite the gunpowder charge.