Sako developed the 7x33 cartridge based on the 9x19 pistol cartridge, by making a longer case and 'necking' the case down to 7mm calibre (7.21mm bullet diameter).
The first civilian rifle bearing the Sako name was the L42 Luodikko rifle model 1942, chambered for the 7x33mm Sako cartridge, prototyped in 1942, and commercial production started after WWII as model number L46. Background and history of the Sako commercial rifle:
