The cartridge is a cylindrical case of metal, paper, or other material, containing the charge and usually the projectile for a firearm.
The cartridge was introduced in the late 16th century. Before its appearance, gunpowder and bullets were carried in separate containers, making the loading process unwieldy and time-consuming. The first cartridges were merely charges of gunpowder wrapped in paper. The bullet or ball was still loaded separately. Refinements were gradually made, and by the end of the 17th century both ball and powder were wrapped together. As weapon technology advanced, other important changes and improvements were made in the design of cartridges.
Today the cartridge case is usually metallic and cylindrical, with a percussion cap in the center of the base. Inside the case is the propelling charge. The bullet is inserted in the open end of the case. A blank cartridge contains only the charge. The modern army requires many different types of cartridges. These include armor-piercing, tracer, incendiary, and grenade cartridges. Brass has been found to be the best metal for cartridge cases, because it is strong, is nonrusting, and can be reloaded and used many times.