Which riffle on which SIG SG 550 is based is a 5.56×45mm NATO assault rifle developed in the early 1970s by Schweizerische Industrie Gesellschaft?
SIG SG 540 The SG 540 is a 5.56×45mm NATO assault rifle developed in the early 1970s by Schweizerische Industrie Gesellschaft (SIG, currently SAN Swiss Arms AG) based out of Neuhausen, Switzerland as a private venture primarily destined for export markets and as a potential replacement for the 7.5×55mm Swiss SG 510 automatic rifle known as the Stgw 57 in Swiss service.
Swiss Arms SAN Swiss Arms AG is a Swiss manufacturer of armaments. It was known as SIG Arms AG before 2000 when it was acquired by the German investors Michael Lüke and Thomas Ortmeier from parent company "Schweizerische Industrie Gesellschaft" (SIG). The Castelli Moser family from Lugano owns the 20% of the factory.