Complete upper fully assembled and ready to install on an AR-15/M16/M4 lower receiver Every component is carefully manufactured, finished, and tested to meet or exceed current military specifications to produces a reliable, smooth-functioning rifle M4-profile, 16" barrel is chambered for military 5.56 NATO ammo; cutout for grenade/tear gas/bean bag launcher Hard-chromed chamber and bore to resist corrosion Barrel is high-pressure tested and magnetic particle inspected to ensure strength and durability Extended M4 feed ramps for reliable feeding during rapid fire Receiver top and carrier are discretely laser-etched with Spike's Tactic Mfg: Spikes Tactical SPECS: Receiver - 7075 T6 aluminum, hardcoat anodized, black. MIL-B-11595E chrome-moly-vanadium barrel, chrome lined, phosphate coated, black. Bolt/Carrier - 8620 steel, Parkerized, matte black. 1-7" twist. Chambered for 5.56mm NATO. Fits mil-spec lower receivers with .250" pivot/takedo