Alpha Carbine 5.56x45mm NATO/.223 Remington 16 Inch Barrel Black 30 Round. Semi-automatic gas impingement system. Features: 13 inch Alpha Rail with Built-In Flip-Up BattleSight, Standard Troy Rear BattleSight, Squid Grips, Pinned Medieval Flash Suppressor, Proctor Sling and the newly released PDW stock. Forged lower receiver, M4A4 flat top forged upper receiver, M4 feed ramps, enhanced trigger guard, Mil-Spec hardcoat anodized finish. Manual lever safety with indicator markings on both sides of receiver.