Caseless ammunition, Gun Wiki
Caseless ammunition refers to small arms ammunition that packages the primer, propellant and projectile together without a cartridge case. They are fired using either mechanical or electronic means to ignite the primer. This design has different characteristics compared to traditional modern metal-cased cartridges. It a subject of some debate as to whether ammunition where the "casing" is metallic but part of the projectile and fired along with it, such as the Volcanic Ball, Soviet VOG grenades
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