Caseless ammunition

Caseless ammunition (CL), or rather caseless cartridge, is a configuration of weapon-cartridge that eliminates the cartridge case that typically holds the primer, propellant and projectile together as a unit. Instead, the propellant and primer are fitted to the projectile in another way so that a cartridge case is not needed, for example inside or outside the projectile depending on configuration. Caseless ammunition is an attempt to reduce the weight and cost of ammunition by dispensing with the case, which is typically precision made of brass or steel, as well as to simplify the operation of repeating guns by eliminating the need to extract and eject the empty case after firing. Its acceptance has been hampered by problems with production expenses, heat sensitivity, sealing, and fragility. Its use to date has been mainly limited to prototypes and low-powered guns, with some exceptions. Older caseless ammunition typically uses a configuration where the primer and propellant get integrated into the bottom of the projectile, much like a rocket. When fired, the propellant gas is vented out the back of the projectile to accelerate it to speed. Unlike rocket projectiles, which have similar configurations, the propellant of "internal propellant caseless ammunition" has an instant burn time like a traditional cartridge (under 0.2 seconds), meaning the propellant burns up before the projectile leaves the barrel, preferrably inside the chamber. Rocket projectiles, in comparison, have propellant burn times of over 0.2 seconds, usually several seconds, meaning rocket propellant traditionally propels the rocket for a certain distance from the launcher. Another difference is means of fire and stabilization. As a cartridge, internal propellant caseless ammunition is only fired from gun barrels, either closed or recoilless, and achieves ballistic stabilization through longitudinal spinning (conservation of angular momentum), either by the use of driving bands and rifling or oblique nozzles for the propellant gas.