The 9×25mm AUPO is an experimental military cartridge developed by Fiocchi Munizioni specifically for use in the Benelli CB-M2 submachine gun.


Similar to the ubiquitous 9×19mm Parabellum in terms of ballistics and physical measurements, the 9×19mm AUPO round was advertised as caseless, but not in the context of a solid block of propellant with a bullet inside of it, as the cartridge's "case" was permanently attached to the bullet, and left the barrel together with the bullet when firing. The powder is packed in the hollow interior behind the permanently-affixed bullet with the cartridge using a ring primer built into the casing. The powder, along with the ring primer, is sealed inside with a lid of lacquer or resin.


  • A similar form factor of a projectile and casing consolidated into a single piece exists in the Russian 40×53mm grenade.