The sheet metal stamping techniques used in making the German MP 40, the British Sten, and the Soviet PPSh-41 and PPS-43 were studied in detail.

Accessories include a special sub-calibre barrel (painted silver) for firing blanks and low-powered gallery ammunition.

Other accessories include night sights (wartime use only) that attach to the fixed day sights (f: protected post, r: L-type), a brass catcher for collecting spent cartridges (peacetime use only, for reloading and recycling),[5] a quick-detachable (by attached cord) ejection port cover (painted bright red) for guard duty which secures the bolt from accidental firing, and a magazine loader that loads a magazine from a cartridge tray in seconds.

The 36-round straight detachable staggered row box magazine is wider at the rear than at the front, the extra space allows the tapered 9mm Parabellum cartridges to feed more efficiently.

The magazine was used post-war by Finland in the m/31 Suomi under the designation m/54, a distinguishing feature of the variation m/55 (made by Lapua) is a steel wire carrying loop mounted at the bottom front edge.

When the m/45 is unloaded the bolt is locked in place in the bolt-forward position by pushing the cocking handle inwards, engaging a hole in the lower left receiver wall.

On 2 April 2007 the kpist m/45 was officially declared obsolete when it was retired from the Home Guard who were the last users in the Swedish Armed Forces.

[9] The US Navy was so impressed by the m/45 that when Sweden embargoed the export of weapons to the United States in 1966, Smith & Wesson was given the task of producing a copy.

[11] In 1975, the Revolutionary Coordinating Junta, a Cuban-backed far-left internationalist organization, established a clandestine military factory in Buenos Aires.

In order to revert this, a Bolivian engineer, nicknamed "Comrade N", aiming to design "a submachine gun with the characteristics of an Uzi, but easier to build and disassemble and using 9mm ammunition" came out with the JCR-1.