Caliber: 5.56 NATO - Action: Semi-auto - Operating System: Closed rotating bolt long gas stroke on piston head - Magazine Type: Polymer NATO STANAG type - Magazine Capacity: 30 rounds - Barrel Material: Cold hammer forged CrMoV chrome lined - Barrel Length: 18 - Overall Length: 27 5/8 - Weight: 8.15 lbs. - Rifling: Right hand 6 grooves 1:7 inch twist - Stock Color: Flat Dark Earth - Stock Type: Reinforced polymer bullpup configuration - Sights: Folding front sight (blade) with Tritium insert and rear sight (aperture)