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.
Assault gun An assault gun is a form of self-propelled artillery which utilizes an infantry support gun mounted on a motorized chassis, normally an armored fighting vehicle. Assault guns are designed to provide direct fire support for infantry attacks, especially against other infantry or fortified positions. The term is a literal translation of the German word "Sturmgeschütz", which was applied to the first purpose-built assault gun, the StuG III, in 1940.