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 UMP The UMP ("Universale Maschinenpistole", German for "Universal Submachine Gun") is a submachine gun developed and manufactured by Heckler & Koch. The UMP has been adopted by various agencies such as the U.S. Customs and Border Protection. Heckler & Koch developed the UMP as a lighter and cheaper successor to the MP5, though both remain in production.