The simple outward appearance of the modern shotshell conceals several important elements which play a critical role in making this form of ammunition fire. The case, crimp, powder, primer, shot and wad all come together to ensure your shotshells fire safely and accurately every time. Click on each term or to learn more about their importance and function in today’s modern shotshell construction.
Case (a.k.a. The Hull) – The modern shotshell case is similar to the case on a rifle or pistol cartridge. The hull is normally made from plastic, paper or, in rare cases, brass. It will also have a steel or brass head and rim attached. The case is designed to contain the powder charge, primer, wad and shot. Hulls are available in a variety of lengths such as 2.75”, 3”, 3.5”. The length of the hull refers to the overall length when the shotshell is fired.
Powder –The term for any chemical compound that is used to propel the shot and wad out of the barrel when ignited by a struck primer. Powder is commonly found in two varieties, smokeless and black. Smokeless powder found in modern ammunition has a significantly reduced smoke signature. Black powder, on the other hand, is very smoky and can be corrosive.
Shot – The shot is the collection of small pellets that act as the projectile in a shotshell. They are commonly made of lead, steel or bismuth. The size of shot varies depending on application.
Primer – The primer is the small circle on the base of the shotshell. The Primer is made up of the anvil, primer cap and priming compound. When the primer is struck by the firing pin it ignites the powder contained inside the case.
Crimp – This is how the shot is retained in the case. There are two main types of crimps: roll and folded. The folded type of crimp is the most common on shotshells. Some roll type crimps will decrease capacity of your shotgun due to the extended length of the crimp.
Wad – The wad is a disk or cup that is used to separate the powder from the shot. It also seals the propellant gases behind the shot column to provide the best level of velocity.