Caliber: .308/7.62x51mm. Capacity: 20. Barrel: 16 in., 1:10 twist, 5/8-24 tpi muzzle threads, fluted stainless steel heavy, cryogenically treated, A2 flash hider. Upper/Lower Receivers: RRA BT-3 Billet A4 Upper; RRA BT-3 Billet lower. Stock: RRA 6-position Operator CAR. Sights: None, optics-ready full-length top rail. Weight: 8.2 lbs. Trigger: RRA Two-Stage. Length: 35 to 37.5 in. Features: Low-profile gas block, mid-length gas system, RRA lightweight free-float rail, 13-in. extended, M-LOK compatible. Introduced 2020.