Case, primer, propellant, and bullet
Aside from some exceptions such as shot shells, standard cases used by reloaders are made of brass. The case provides the housing for bullet, propellant and primer. Its primary task is to create a gas-tight seal in the chamber against the gas pressure developing when the cartridge is fired.
The primer cap (short: primer) is used to ignite the propellant. There is a distinction between Berdan and Boxer primers. Both types consist of a capsule containing the priming compound, which is usually sealed with protective varnish. The boxer primer has the anvil included.
The most commonly used type of propellant today is the so-called smokeless powder. The name was derived from the term ‚black powder‘, even though granular types have long replaced propellant in powder form.
The smokeless powders we use today are quite a novelty compared to black powder. The first
smokeless powders were only introduced shortly before the end of the 19th century, some 500
years after the first experiments with black powder.
Bullets are available in a wide range of types and designs, each made for a specific purpose. Hunting bullets must ensure a high terminal performance in order to deliver sufficient energy for a clean, instant kill of the game animal. Target bullets have a different performance objective: accuracy. Bullets used for military purposes are designed for very specific requirements. Bullet mass and shape are usually matched to the barrel‘s length and twist rate.