Schweizerische Industrie Gesellschaft
The SG 510 is derived from the AM55 developed during the late 1950s. During its development Rudolf Amsler was the principal designer at Schweizerische Industrie Gesellschaft. It is a selective fire rifle that employs a roller-delayed blowback operating system. The Stgw. 57 was used by the Swiss Army as a personal universal weapon. In Swiss service it gradually replaced the K31 rifle, the Suomi M-31/Mp. 43/Mp. 44 submachine gun, the Lmg 25 light machine gun, and after 1974-1977 the Zf. Kar. 55 designated marksman rifle.