Anatomy of a Shotgun Shell
Article by Greg
Many folks new to the shooting sports often become confused by the myriad of different ammunition available for shotguns. When you consider the fact that shotgun ammunition covers a diverse spectrum of projectiles such as birdshot, buckshot, slugs and other specialty varieties it's not difficult to understand where people get lost.
To really understand what a shotgun shell is we need to start by breaking it down into it's core components. A shotgun shell is a self-contained cartridge meaning it can simply be loaded into a shotgun and fired without any special preparation or additional parts. It consists of a primer, a hull, a powder charge, a wad and a projectile load.
The hull is essentially a container for all the other components. Most modern shotgun hulls are made of plastic with a metal base however paper and metal hulls are also occassionally seen in use today as well, although for the most part these are a thing of the past. Aside from the obvious purpose of keeping all the components together, hulls are also responsible for keeping the powder charge dry (one of the main reasons paper hulls have become obsolete) and sealing the explosive gases formed during discharge and ensuring they exit via the barrel as opposed to through the breach.
The primer is a small, metal cup located in the base of the hull that contains a chemical compound which ignites when struck, this is used to detonate the powder charge which causes the shell to fire.
The powder charge is a small amount of gunpowder measured in grains, relatively stable on it's own, the powder charge relies on the primer to ignite it.
The wad is essentially a piece of plastic which sits between the powder charge and the projectile load. The wad actually serves several purposes; it keeps the powder and the projectile load seperated, and, when fired, allows the projectile load to travel down the length of the barrel without actually touching the inside of the gun, thereby preventing any damage to the firearm from scratching or scoring.
The projectile is typically made up of shot; small metal balls designed for a number of different applications such as hunting, target shooting and self-defense or slugs; a single, large-caliber bullet used for hunting.
When combined, these components form one of the oldest and most versatile ammunitions still in use today.