Great Lakes Firearms AR-15 Features The rifle s barrel is offered in either 416R Stainless Steel or 4150 CRMOV Nitride each with 1/2 x 28 thread patterns. The gas system includes a 0.750 black oxide gas block coupled with a carbine gas tube for consistent performance. The handguard is a 15.25-inch aluminum 6061 model with a full picatinny rail allowing for easy attachment of accessories. Equipped with a mil-spec polymer grip the rifle ensures a comfortable and firm hold. It comes with a 30-round magazine and features a unique muzzle brake that is designed to be 6 degrees forward ensuring stability and control during firing. Great Lakes Firearms AR-15 Specifications Action: Semi-Automatic Ambidextrous Safety: No Barrel: 16 inches 1:8 Twist HBAR (416R SS or 4150 CRMOV Nitride) Caliber: .223 Wylde Feed Ramps: M4 Finish: Cerakote OD Green Frame Material: Aluminum 7075 Gas System: 0.750 Gas Block Carbine Gas Tube Grip: Mil-spec Polymer Handguard: 15.25 Aluminum 6061 Full picatinny rail Magazine Capacity: 30 Rounds Mags Included: 1 Muzzle Brake: 6 degrees forward Wrench tightened Sights: None Trigger: Milspec 5.5-6 lb pull Upper Receiver: 7075 Upper Overall Length: 33.25 inches Weight: 6.8 lbs.