This was a SAKO development, developed between 1942 and 1946. A 2011 article by Juha-Pekka Ripatti on the http://yeswehunt.eu website states: ” The history of this cartridge goes way back into the year 1942 and to the World War II. For obvious reasons Sako produced at that time large quantities of 9 mm Parabellum (9 x 19 mm) cartridges. These cartridges were used in Suomi submachine gun and Lahti L-35 military pistol which were designed by Master Armorer Aimo Lahti of the Finnish Army. For hunting purposes the case base stayed equal to 9 mm Para but the case was lengthened to the maximum possible for the available case-making equipment. After that it was necked down to 7 mm”. (Dixon Ref. SC46)