 The more powerful ammunition resulted in significant recoil, which was problematic for the gunner, and its size made portability difficult.The Solothurn firearms company was owned by the German firm Rheinmetall, who used the Swiss company to manufacture arms which were prohibited for manufacture by any German firm under arms limitations imposed at the end of the First World War.In 1940–1941 the US Army considered adopting the Solothurn S18-1000.