Caseless ammunition

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.

[4] Rockets, in contrast, can be fired from more platforms than gun barrels, for example, rails, and traditionally use fins for stabilization, either fixed or foldable.

Named Ho-301, it was a 40 mm autocannon and saw limited action in the defense of the Japanese home islands during the waning months of the war.

[4][3] Modern caseless ammunition typically uses a configuration in which the primer and projectile gets integrated into a solid mass of external propellant (originally nitrocellulose), cast to form the body of the cartridge.

The completed cartridge might also contain a booster charge of powdered propellant to help ignite the body and provide initial thrust to the bullet.

A shorter cartridge cuts down on the distance the firearm's action must reciprocate to load a new round, which allows for higher cyclic rates and greater probability of multiple hits on a target at long range.

The first major problem, of special concern in military applications, which often involve sustained firing, is the heat sensitivity of the ammunition.

The thermal insulation provided by the case also works the other way around, shielding the propellant from built-up heat in the chamber walls.

[2][15] Heckler & Koch, in concert with Dynamit Nobel, managed such a task by producing relatively heat-resistant external-propellant caseless ammunition.

This prevents gas exiting from the rear of the chamber, and it has also been experimentally shown to provide a significant amount of support to the bolt.

Even in completely plastic-bodied cartridges, such as the Activ brand shotgun shells, a thin metal ring is molded into the rim to provide support for the extractor.

Primer and propellant in external-propellant caseless rounds is unprotected, while cartridge cases provide a high degree of protection.

While it was scheduled to be adopted by the West German military with a plan set out to procure 300,000 G11K2 rifles over a period from 1990 to 2002, the expenses created by the reunification of Germany and the impossibility of modifying the G11 to use NATO-standard ammunition led to the cancellation of the G11 project and the adoption of a cheaper, more conventional NATO-standardised assault rifle, the 5.56 mm G36.