Daniel Defense M4A1 Complete Upper Features The Daniel Defense M4A1 Complete Upper starts with a mil spec 7075-T6 aluminum upper receiver featuring M4 feed ramps and proper indexing marks for reliable feeding and easy builds. The 14.5 inch chrome moly vanadium steel barrel is cold hammer forged with a 1:7 twist rate and chrome lined bore then pinned and welded to a Surefire SF3P flash hider and suppressor adapter to bring the assembly to a 16 inch overall length. This pinned and welded configuration allows the upper to remain rifle length compliant while still accepting Surefire suppressors via the SF3P interface. A carbine length direct impingement gas system paired with a mil spec F-marked front sight base keeps the system running reliably across a wide range of ammunition. The Daniel Defense M4A1 FSP Rail Interface System II handguard is CNC machined from 6061-T6 aluminum and finished in Type III hard coat anodized Flat Dark Earth giving the upper the same rail profile used on SOPMOD Block II inspired builds. An M16 profile bolt carrier group chrome lined and mil spec MP tested with a properly staked gas key provides full auto rated durability for hard use. A fixed A1.5 rear sight machined from 6061-T6 aluminum rounds out the sighting system and a rail mounted QD swivel attachment point with QD swivel is included for sling attachment. This Daniel Defense M4A1 Complete Upper is available for sale at GrabAGun as a complete ready to install upgrade for AR-15 platform rifles. Daniel Defense M4A1 Complete Upper Specifications Manufacturer: Daniel Defense Model: M4A1 Complete Upper Caliber: 5.56 NATO Barrel Length: 16 (14.5 Pinned) Barrel Material: Chrome Moly Vanadium Steel Twist Rate: 1:7 Barrel Finish: Chrome Lined Phosphate Coated Gas System: Carbine Length Direct Impingement Muzzle Device: Surefire SF3P Flash Hider/Suppressor Adapter Bolt Carrier Group: M16 Profile Chrome Lined Sights: A1.5 Fixed Rear Sight F-Marked Front Sight Base Handguard: Daniel Defense M4A1 FSP RIS II Color: Flat Dark Earth Finish: Anodized Material: Steel Aluminum Includes: QD Swivel Available At: GrabAGun