A bullet is a small, metal projectile designed to be fired from a firearm. It is typically cylindrical in shape and can vary in size, weight, and design depending on its intended use. Bullets are commonly made from lead, copper, or other materials and are used in various types of guns, including handguns, rifles, and shotguns. When a bullet is fired, it is propelled by the rapid expansion of gases produced by igniting gunpowder within the cartridge. This process allows the bullet to travel at high speeds, making it effective for purposes such as hunting, sport shooting, and self-defense.