Spikes Tactical Upper 5.56 14.5in 16in OAL CHF Midlength w/12in BAR2 Rail w/ Dynacomp. We maintain our high standard of tolerances and attention to detail as the uppers we use for complete rifle builds. Every built upper and complete gun is test fired before leaving our facility for function check before it reaches you. Specifications for Spikes Tactical 5.56 Cold Hammer Forged 14.5in Upper Receiver: Manufacturer: Spikes Tactical Caliber: 5.56x45mm NATO Overall Length: 16 in Barrel Length: 14.5 in Barrel Profile: Optimal Barrel Twist Rate: 1-7 Firearms Threads Per Inch: 1/2x28 Finish: Nitride Inside and Ou Mil-Spec Type 3 Coating Color: Black Gun Model: AR-15 Condition: New Weight: 3 lb Magazine Included: No Country of Origin: USA Features of Spikes Tactical 5.56 Complete Upper Receiver w/Cold Hammer Forged 14.5in Barrel: Forged Upper Receiver - 7075 T6 Construction Forward Assist Ejection Port Door Ejection Port Door Spring Ejection Port Door Rod. 14.5-inch Mid Length Cold Hammer Forged Optimal Profile Barrel. Forged Aluminum Charging Handle with Mil-Spec Type 3 Coating. Phosphate M16 Complete Bolt Carrier Group - Phosphate Coated Laser Engraved with ST Spider logo High Pressure Tested (HPT) Magnetic Particle Inspected (MPI). Package Contents: Spikes Tactical 5.56 Cold Hammer Forged Barrel 14.5in Upper Receiver What firearm models does the manufacturer say Spikes Tactical 5.56 Cold Hammer Forged 14.5in Upper Receiver is compatible with? The manufacturer suggests that Spikes Tactical 5.56 Cold Hammer Forged 14.5in Upper Receiver is compatible with AR-15Spikes Tactical STU5420-R2D: Upper 5.56 14.5in 16in OAL CHF Midlength w/12in BAR2 Rail w/ Dynacomp