Caseless cartridges reduce ammunition weight by 50%, though firearms require special modifications to fire it.
Caseless cartridges fully burn up within the chamber and the barrel when fired, leaving no residue behind. These offer the greatest weight and space savings of all small arms ammunition types save for exotics such as magnetic slugs but are extremely hard to manufacture and require specialised internal mechanisms. Prototypes for caseless autocannon ammunition have been somewhat more successful.