The Swiss SIG SG550 assault rifle is based on the SG540. It entered into production in 1981 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). As special attention was paid to making it lighter, the butt, handguard and magazine are largely made of plastic.
