The SIG SG550 5.56×45mm NATO assault rifle designed and manufactured by Swiss Arms AG (former division of SIG Holding AG), adopted into service in 1990. It features a reciprocating charging handle, a folded stock, an ambidextrous safety, closed bolt gas-actuated long-stroke piston mechanism and manually adjustable gas valve which make the rifle very reliable.
This tag can also apply to the slightly shorter SG551 variant, and the discontinued semi-auto only SG550-1 for designated marksman role (with a scope and bipod).
