Spikes Tactical Upper 5.56 8.1in CHF Barrel w/7in SAR3

Spikes Tactical Upper 5.56 8.1in CHF Barrel w/7in SAR3. Spikes Tactical maintains their high standard of tolerances and attention to detail as the uppers they use for complete rifle builds. Every built upper and complete gun is test fired before leaving the facility for function check before it reaches you. Specifications for Spikes Tactical 5.56 Cold Hammer Forged 8.1in Upper Receiver w/7in SAR3: Manufacturer: Spikes Tactical Caliber: 5.56x45mm NATO Barrel Length: 8.1 in Finish: Anodized Color: Black Gun Model: AR-15 Magazine Included: No Additional Features: w/7in SAR3 Rail Country of Origin: USA Features of Spikes Tactical 5.56 Cold Hammer Forged 8.1in Upper Receiver w/7in SAR3: Forged Upper Receiver 7075 T6 Construction Forward Assist Ejection Port Door Ejection Port Door Spring Ejection Port Door Rod 8.1in Cold Hammer Forged Barrel DIN 21CrM0V511 1/7 Twist Rate 1/2 X 28 Thread Pitch for Muzzle 5.56 Nato Chamber .750 Gas Block Seat M4 NIB Coated Barrel Extension Black Nitride Coating 7in SAR3 Rail 7075 T6 Barrel Nut 6061 T6 Rail Continuous Top Rail Free Floating 1 Piece Q.D Attachment Points Low Profile Gas Block Solid Billet Steel .750 I.D Pistol Gas Tube Black Nitride Inside and Out Gas Tube Roll Pin Charging Handle Forged Aluminum Mil-Spec Type 3 Coating Phosphate M16 Complete BCG Phosphate Coated Laser Engraved with ST Spider logo High Pressure Tested (HPT) Magnetic Particle Inspected (MPI) A2 Flash Hider 1/2in Crush Washer Weight: 3lb 5oz Package Contents: Spikes Tactical 5.56 Cold Hammer Forged 8.1in Upper Receiver w/7in SAR3 What firearm models does the manufacturer say Spikes Tactical 5.56 Cold Hammer Forged 8.1in Upper Receiver w/7in SAR3 is compatible with? The manufacturer suggests that Spikes Tactical 5.56 Cold Hammer Forged 8.1in Upper Receiver w/7in SAR3 is compatible with AR-15Spikes Tactical STU5181-CQ7F: Upper 5.56 8.1in CHF Barrel w/7in SAR3