This was a “Pistolengewehr” development dating from around 1921 by Swiss engineer Adolf Furrer, who was the director of Waffenfabrik Bern. The Pistolengewehr was a toggle-action short-recoil operated weapon with a side-mounted 30 round magazine with a wooden stock. It was based on a shortened 7.5×55 GP11 case which used a 123gr round-nosed bullet at a little over 2,000 fps. WWI had taught designers like Furrer that more firefights took place at shorter distances, for which the GP11 was kind of over-powered. The idea was making a smaller cartridge so the soldier could carry more ammunition and a new magazine fed semi-automatic service rifle for more fire power.

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