Centerfire cartridges are by far the most prevalent form of ammunition today. The term "cartridge" originates from a paper tube filled with powder or powder and a bullet used in muzzle loading firearms. Developments in metallic cartridges in the 19th century included needlefire cartridges, pinfire cartridges, and rimfire cartridges. The rimfire design is still in wide use in .22 caliber cartridges. The centerfire design emerged first in shotguns in the 1850s.
The modern centerfire cartridge was independently developed by Englishman Edward Boxer and the American Hiram Berdan in the mid-1860s. The Berdan and Boxer cartridges differ primarily in primer design. Boxer primers are more common in US ammunition, Berdan primers are mostly seen in European and Asian ammunition. While there have been many developments in firearms design, the basic architecture of the centerfire metallic cartridge remains the same today as when it was perfected by Berdan and Boxer.
Centerfire cartridges are by far the most prevalent form of ammunition today, but the term "cartridge" originally referred to a paper tube filled with powder and, later, both powder and a bullet. These were used in muzzle loading firearms. Carrying a pre-measured portion of powder saved the shooter time in that they did not have to measure out powder from a flask every time they loaded their firearm.
In the 19th century, many different designs for metallic cartridges emerged. These included needlefire cartridges, in which a needle pierced the cartridge and ignited a percussion cap at the base of the bullet, pinfire cartridges in which a pin perpendicular to the case ignited the primer, and rimfire cartridges, in which the primer is in the rim and ignited when the firing pin crushes a small section of the rim.
The rimfire design is still in wide use in .22 caliber cartridges. A drawback of rimfire cartridges is that they must be made of relatively thin metal to allow the rim to be crushed, and thus can not handle high pressures. The centerfire design emerged first in shotguns, and the shotgun shells introduced in the 1850s with primers in the center of brass and paper uppers are largely the same in design as shot shells today -- the only difference is that contemporary shells now generally use plastic rather than paper for the uppers.
The modern centerfire cartridge was developed in slightly different forms at almost exactly the same time by Englishman Edward Boxer and the American Hiram Berdan, both army officers, who independently developed designs for primers that fit into the base of a metallic cartridge. Both had finalized their designs by the mid-1860s. The Berdan and Boxer primers differ in design in that the Berdan primer uses a dome that is crushed by the firing pin, whereas the Boxer primer uses a small cap that is driven against a plate by the firing pin.
The Boxer primer is pressed into the cartridge, making it relatively easy to remove and replace for reloading. The Berdan primer, by contrast, is formed into the case head, and it is much more difficult to reload a Berdan-primed cartridge. In modern ammunition, Boxer-primed cartridges are more common in commercial ammunition from manufacturers in the United States. Berdan-primed cartridges are generally encountered in military-surplus ammunition from European and Asian countries.
The introduction of smokeless powder and the ability to manufacture ammunition to exacting tolerances allowed many developments in firearms design, but the basic architecture of the centerfire metallic cartridge remains the same today as when it was perfected by Berdan and Boxer.