The four basic parts of a bullet are the case, projectile, primer, and powder.

  1. Case: Made of brass, steel, or copper, the case is exactly what it sounds like. It’s the case, the foundation of ammunition. It contains the primer, powder, and projectile. Companies that prioritize case design generally have better-performing ammunition overall.  For shotgun shells, this is commonly referred to as the shell.
  2. Projectile: The projectile refers to the bullet propelled from the case and out of the barrel once you pull the trigger. For a shotgun shell, this refers to the shot or slug that leaves the shell and exits the barrel.
  3. Primer: The primer is the component that ignites the gunpowder inside the case or shell, causing the projectile to be propelled down the barrel.
  4. Powder: The gunpowder is ignited by the primer and creates an explosion, producing high amounts of pressure that propel the projectile from the case and down the barrel of the firearm.
What Are The 4 Basic Parts of Ammunition
HOP Munitions 9mm Polymer Ammo components (Photo: HOP Munitions)

Shotgun Shells contain an additional component called the WAD.

The wad in a shotgun shell is usually made of plastic, compressed paper, or felt and serves a dual purpose.

First, it provides a barrier between the powder charge and projectile, preventing the gas pressure from blowing through the shot and propelling the projectile down the barrel more consistently.

The second purpose is to keep the shot in a tighter pattern as it travels down and exits the barrel.

Old vs. New shotgun shell WAD design

The green shell is the old-school military 00 buck. The Maroon colored shell is Federal with Flitecontrol WAD.

shotgun shell WAD design

The WAD for the military 00 buck is made from two compressed paper wads and a plastic wad separating the nine projectiles from the gunpowder. The Federal 00 Buck, on the other hand, uses a single Flitecontrol WAD made of plastic that houses the nine projectiles until they exit the barrel.