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.
FA-MAS Type 62 The FA-MAS Type 62 is a 7.62×51mm NATO rifle developed by the French Army as a replacement for the MAS-49/56. It was the last in series of 40 different prototype rifles designed between 1952 and 1962, and bears a resemblance to the FN FAL. However, the introduction of the 5.56×45mm cartridge caused the French to rethink their approach and the project was eventually cancelled. The Type 62's bayonet was later adopted for use on the FAMAS rifle.