Daniel Defense manufactures the highest quality complete AR15 upper receivers on the market today. The M4 URG, MK18 comes complete with a bolt carrier group, charging handle, 10.3 inch Cold Hammer Forged Barrel, RIS II MK18 Rail System that is finished in Flat Dark Earth, and a Daniel Defense low profile gas block.The Daniel Defense MK18 Upper Receiver Group features the railed forend Daniel Defense currently provides to USSOCOM and a 10.3 inches Cold Hammer Forged Barrel. The MK18 Rail Interface System (RIS II) features the Bolt-Up System has been rigorously tested prior to fielding by USSOCOM. The 10.3 inches barrel is the same length in use for the MK18 upper most commonly used for CQB operations. The new independently ambi GRIP-N-RIP Charging Handle accommodates left- and right-handed shooters and is engineered for suppressed fire, with anti-gas features that redirect gas flow upward and away from the face and operator. All Daniel Defense complete upper receiver groups come standard with an M16 profile bolt carrier group. Feature: Upper receiver: Mil-Spec with indexing marks and m4 feed ramps, CNC machined of 7075 T6 aluminum, type iii hard coat anodized Barrel: chrome moly vanadium steel, cold hammer forged, 1:7 twist, 10.3 inches government profile, chrome lined, mil-spec heavy phosphate coated, and HP/MPI tested Gas system: pinned low profile gas block cnc machined of 4140 hardened steel with mil-spec heavy phosphate coating, carbine length, direct impingement Muzzle device: daniel defense flash suppressor, 17 to 4 ph stainless steel, salt bath nitride finished Bolt carrier group: m16 profile, mil-spec mp tested, chrome lined, properly staked gas key Handguard: daniel defense ris ii MK18, cnc machined of 6061 T6 aluminum, type iii hard coat anodized Charging handle: Grip-N-Rip charging handle, body CNC machined of 7076 T6 aluminum, handles and latch cnc machined of 6061 T aluminum, heavy duty stainless steel roll pins, type III hard coat anodized Rail panels: daniel defense rail panels made from santoprene, heat resistant to 300 deg F Made in USA