Designed in the 1970s as the 7.62x51mm SIG SG 540 series, this interesting modern combat rifle never really caught on except in Latin America, where it is still in production. Larry Vickers shows off the FAMAE (Fábricas y Maestranzas del Ejército) SG 543, a select-fire gas operated rotating bolt rifle in 5.56mm NATO, in the above video.