An ammo shooter is a person who is responsible for the loading, firing, and maintenance of ammunition. The term can be broken down into four parts: PEA (3 letters), PEAS (4 letters), STEN (4 letters), and CAPS (4 letters). PEA stands for Projectile Explosive Ammunition, PEAS stands for Projectile Explosive Ammunition Shooter, STEN stands for Small Arms Training Equipment, and CAPS stands for Combat Arms Proficiency System. Together, these terms refer to the job of an ammo shooter.