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.
MAS-49 rifle The MAS-49 is a French semi-automatic rifle that replaced various bolt action rifles as the French service rifle that was produced from 1949. It was designed and manufactured by the government-owned MAS arms factory. The French Army formal designation of the MAS-49 is Fusil Semi-automatique de 7,5mm Modele 1949 ("semi-automatic rifle of 7.5mm model 1949"). The MAS-49 semi-automatic rifle was produced in limited quantities (20,600 units), whereas the shorter and lighter variant, the MAS-49/56, was mass manufactured (275,240 units) and issued to all branches of the French military. Overall, the MAS-49 and 49/56 rifles gained the reputation of being accurate, reliable and easy to maintain in adverse environments. All the MAS-49 and 49/56 rifles feature a rail on the left side of their receivers to accommodate a designated rifle scope. The MAS-49 and MAS-49/56 were replaced as French service rifles by the FAMAS assault rifle in 1979.