223 Rem. / 5.56mm NATO. Semi-Automatic, Gas Impingement System. Capacity: 30 + 1- Ships with one 30 Round Magazine (accepts all std. sizes). Safety: Manual Lever with Indicator Markings Both Sides of Receiver. Receiver: M4A4 Type Flat Top Upper Receiver. Receive Material: Forged 7075 T6 Aircraft Aluminum with Aluminum Trigger Guard. Receiver Finish: Hardcoat Black Anodize Finish. Barrel: 16" M4 Profile, Chrome Lined with. A2 Flash Suppressor. Barrel Material: 4150 Chrome Moly Vanadium Steel. Rifling: 1 Turn in 9" - Right Hand Twist. Stock: 6-Position Telescoping Buttstock with Windham Weaponry Logo. Forend / Pistol Grip: M4 Double Heat Shield Handguards / Black Plastic Grip. Rear Sight: None - Ready for optics or other type accessory sights. Front Sight: None - Picatinny Rail Gas Block - Ready for accessory sights. Packaging: Hard Plastic Gun Case with Black Web Sling & Operators Manual. Weight: 6.3 lbs.