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). 
Heckler &amp; Koch HK417 The Heckler & Koch HK417 is a battle rifle designed and manufactured by Heckler & Koch in Germany. It is a gas-operated, selective fire rifle with a rotating bolt. It is chambered for the full-power 7.62×51mm NATO round, instead of the less powerful 5.56×45mm NATO intermediate cartridge. The HK417 is intended for use in roles where the greater penetrative power and range of the 7.62×51mm NATO round are required. It has been adopted for service by a number of armed forces, special forces, and police organizations.