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 550 The SG 550 is an assault rifle manufactured by Swiss Arms AG (formerly a division of Schweizerische Industrie Gesellschaft now known as Sig Holding AG) of Neuhausen, Switzerland. "SG" is an abbreviation for "Sturmgewehr", or "assault rifle". The rifle is based on the earlier 5.56mm SG 540 and is also known as the Fass 90 ("Fusil d'assaut" 90/"Fucile d'assalto" 90) in French/Italian or Stgw 90 in German ("Sturmgewehr" 90). 
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.