The DPMS Oracle AR-15 Upper Receiver Assembly comes completely assembled and ready for installation on any standard small pin, mil-spec lower receiver. The Oracle is an excellent entry-level upper assembly that incorporates the versatility of the A3 Flat-Top configuration in selecting a preferred sighting arrangement with a solid, fully functional foundation of quality components. Add to that an attractive price and the Oracle becomes the ideal candidate for shooter customization and/or for assembling a lightweight, fast handling, general purpose carbine that won't break the bank. The Oracle features a 16" Light Contour "Pencil" Barrel for reduced weight, a true 5.56x45mm NATO chamber for use with either commercial or mil-spec ammunition, and employs the versatile 1 in 9" rifling twist rate capable of stabilizing a wide selection of different bullet weights. The upper comes equipped with heat resistant GlacierGuard polymer handguards, single rail gas block, ejection port door, forward assist, shell deflector, charging handle, complete bolt & carrier assembly, and an A2 flash hider. Aluminum parts are hard coat anodized to mil-spec, steel parts are manganese phosphate treated (parkerized) matte black. All DPMS upper receivers are factory test fired for functionality before shipment. Notes: Installation of AR-15 upper assemblies with certain features including, but not limited to: flash hiders, bayonet lugs, and threaded muzzles.