CMMG COMPLETE UPPER 16" 1:9 WASP M4 BARREL & MICRO-GAS BLOCK This complete upper from CMMG features a 1:9 twist M4 profile 16 inch barrel with their Weapons Armored Surface Protection (W.A.S.P.) proprietary finish which eliminates the need to chrome line the bore and provides better accuracy along with increased durability and reliability. WASP coating is harder than chrome and provides greater durability. Comes complete with charging handle, bolt and bolt carrier. These uppers also come with the CMMG Micro Gas Block factory installed, so all you need to do to put a 10 or 12 inch free float rail from Midwest, Samson or Troy on it is cut the delta ring off and install the rail! We can do this for you if you'd like, just give us a call to discuss options. FITS: Bushmaster, DPMS, Olympic Arms, Rock River Arms, Spike's etc guns. Colt (MIL-SPEC TYPE ONLY!) CMMG M4 Profile Uppers have the following standard features. Mil-spec certified 4150 chrome-moly vanadium steel M4 contour barrel 1/7 twist Hard chrome lined chamber and bore Notched M4 handguard cap Chrome-lined 5.56mm x 45 NATO chamber and bore M4 feed ramps Magnetic particle testing on every barrel 11 degree recessed target crown F marked forged front sight base Parkerized Barrel including under the front sight base A2 Flash hider installed with Peel washer Forged A3 upper receivers are T marked and have extended feed ramp cuts (M4 ramps). Semi Auto bolt carrier Each barrel is individually magnetic particle tested. Barrels are engraved CMMG MPC 5.56 NATO 1/7. Each Upper is head spaced and test fired before shipping. Upper specific features are listed with the individual item. When selecting the gas piston operating system, it will override your choices for the bolt carrier and front sight/gas block. COMPLETE UPPER ONLY. CARRY HANDLE & ACCESSORIES NOT INCLUDED