Bullet

A bullet is a type of projectile that is shot from the barrel of a firearm. Bullets are made of a variety of materials, including copper, lead, steel, polymer, rubber and even wax. They do not normally contain explosives, but are kinetic projectiles that strike or damage the target by transferring kinetic energy upon impact and penetration. They are made in shapes and constructions that vary for different applications, including specialized functions such as hunting, target shooting, combat, and training. They are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter (referred to as "caliber") in both imperial and metric measurement systems.