This document summarizes the key components of ammunition. It defines ammunition as containing projectiles, fuses, propelling charges or primers according to the Arms Act of 1959. The main components are then described in more detail: the cartridge case holds all other components, the primer contains an explosive mixture to ignite the powder, and powder/propellant provides kinetic energy to propel projectiles. Projectiles can be bullets or shotgun pellets. Wads are used in shotguns to separate components. Lubricants reduce friction. Modern ammunition includes center fire and rim fire cartridges. Metallic and shotgun ammunition are also summarized.