Ammunition types refer to the various categories of projectiles and their casings used in firearms. Common types include bullets, shotgun shells, and cartridges. Each type is designed for specific purposes, such as hunting, target shooting, or self-defense. Within these categories, ammunition can be further classified by caliber, which indicates the diameter of the bullet or shell. Other factors include the type of propellant used and the design of the projectile, such as hollow-point or full metal jacket. Understanding these differences helps users select the right ammunition for their needs.