This discipline addresses how each cartridge case is manufactured, from its starting point as a coin, along with how the projectile is manufactured (which could start as a coin or a bar), how the primer is manufactured, and how the propellant is manufactured. For shotguns, this would also deal with the shot pellets and the wads. Each of these includes a large number of steps, and different machinery, as the part wends its way through the process.
These separate parts are then assembled into a cartridge, which is its own manufacturing discipline. This includes the constant quality control testing and evaluation during manufacture and, upon completion, the testing for final approval to place the cartridges into the stream of commerce.
Of necessity, this includes the DOT (Department of Transportation) requirements for the movement of propellant and the NFPA (National Fire Protection Association) Code requirements for the storage and use of the propellant. Upon completion, this includes the packaging of the cartridges and the other issues for safe shipping of the ammunition by land (DOT), by sea (United States Coast Guard) and by air (International Air Transportation Association).