Create an astonishing rifle build with the craftsmanship and features packed into this Aero Precision M4E1 Threaded 8in .300 Blackout Complete Upper Receiver. Each of these AR15 Upper Receivers designed by Aero Precision contain an ATLAS S-One Handguard that is compatible with low profile gas blocks as well as Mil-Spec AR15 uppers and barrels. This Aero Precision M4E1 Threaded 8in .300 Blackout Assembled Upper Receiver also contains a 4150 Chrome Moly Vanadium barrel with a QPQ finish that protects it from corrosion inside and out, ensuring maximum performance with a long lifespan. Adding this receiver to your weapon build greatly improves your shooting experience. QD sling sockets allow you to attach a sling for comfortable carry, the construction is robust while still remaining lightweight and you can pick which rail best suits you to attach your favorite optics and accessories for enhanced accuracy in the field. Install this Aero Precision M4E1 Threaded 8in .300 Blackout Complete Upper Receiver w/ ATLAS S-ONE Handguard to truly experience what your firearm is capable of at the range, on a hunt or anywhere else you demand high performance with every pull of the trigger. Specifications for Aero Precision M4E1 Threaded 8in .300 Blackout Complete Upper Receiver with Flash Hider: Manufacturer: Aero Precision Cartridge: .300 AAC Blackout Barrel Length: 8 in Gas System Length: Pistol Length Barrel Twist Rate: 1-7 Threads per Inch: 5/8x24 Muzzle Device: A2 Flash Hider Gun Model: AR-15 Condition: New Fabric/Material: Chrome Moly Vanadium Gas Block Journal Size-Diameter: .750 in Handguard Length: 7 in Gun Make: AR Platform Weight: 18 oz Magazine Included: No Country of Origin: USA Features of Aero Precision M4E1 Threaded 8in .300 Blackout Complete Upper Receiver with Flash Hider: M4E1 Threaded Upper Receiver Features: New enhanced forging that gives the upper receiver a "billet look" New Picatinny profile that blends seamlessly with our Enhanced Series Handguards M4 Feedramps .250 takedown pin holes Laser engraved T-marks Includes port door and forward assist installed ATLAS S-ONE Handguard Features: Front and rear Picatinny rail Eliminated center of top rail for weight reduction Indexing grooves in 12:00 position for positive grip control Quick disconnect sling socket at the 3, 6 and 9 o'clock positions Compatible with low profile gas blocks 1.3in Inside diameter 1.5in Outside diameter Compatible with mil-spec AR15 upper receivers and barrels 8in .300 Blackout Barrel Features: Length: 8in Twist: 1 in 7 Muzzle: 5/8x24 Threaded Material: 4150 Chrome Moly Vanadium Finish: QPQ corrosion resistant finish both inside and out Gas Block: .750 Gas Port: .109 Gas System Length: Pistol Weight: 18oz M4 Barrel Extension HP and MPI Tested Package Contents: Aero Precision M4E1 Threaded 8in .300 Blackout Complete Upper Receiver with Flash Hider ATLAS S-ONE Handguard of choice 8in .300 Blackout CMV Barrel Low Profile Gas Block and Pistol Length Gas Tube