It can be argued that this cartridge is nothing more than a longer case length 9mm Parabellum training blank used with a specially constricted barrel and deeper chamber preventing accidentaly firing live rounds as a live round would settle too far forward in the chamber for the firing pin to reach. It was used in the M/49 Hovea SMG originally developed by Sweden for military trials, but after losing out to the Carl Gustaf design, the Danes showed interest and adopted it in 1949. Shown here for interest sake, although classified under 9mm Parabellum.