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.
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.