Spike's Tactical Complete Upper Receiver, 223 Rem/556NATO, 14.5 Barrel (16 OAL with Pinned Brake), Mid-length Gas System, Fits AR Rifles, Black, Flat Top Receiver, No Sights, 12 CRR Quad Rail, Dynacomp Muzzle Brake, No Mags STU5050-CQ2D Spikes complete upper assemblies will arrive to you inspected" tested" and ready to drop-in and go to work. Spikes maintains the same 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 Spikes facility for function check before it reaches you.