This Adams Arms AR-15 A3 Base Mid Gas Piston Upper Assembly is chambered in 5.56x45mm NATO and comes ready to fire right out of the box after installation onto any standard AR-15 lower receiver. This Base Mid upper comes equipped with a 16" melonite-finished barrel, A2 flash hider, bolt carrier group, charging handle, picatinny rail gas block, delta ring assembly and a set of polymer 2-piece handguards. Additional features include a forged A3 flat-top configuration that's ready to accept the shooter's choice of optic and/or rear iron sight, M4 feed ramps to help ensure reliable feeding and functioning during rapid strings of fire, and a mid length gas system for a smoother recoil impulse and longer sight radius.
The upper's barrel has been finished inside and out with Adams Arms' proprietary QPQ Melonite treatment that bonds with the metal on a molecular level. Also referred to as salt bath nitriding, this treatment produces an extremely hard, slick surface on steel that resists carbon adhesion and increases corrosion resistance, extending a barrel's service life by reducing the friction produced inside the bore upon firing for a net decrease in bore surface wear over time. Nitriding converts the barrel steel's surface without any build-up, retaining all of the benefits of traditional chrome lining without suffering the accuracy degradation commonly encountered with it due to the uneven application of chrome inside the barrel's bore. The end result is a barrel that's capable of producing accuracy on par with a match stainless steel tube, while also exhibiting the longevity and resilience of a chrome lined, mil-spec barrel.
All Adams Arms uppers feature a short stroke gas piston operating system, which prevents hot gas and debris from being directed back into the action upon firing. The result is a rifle that runs cooler, cleaner and more reliably than those utilizing a standard direct gas impingement system of operation. To ensure that damage doesn't occur to the buffer tube from carrier tilt, the bolt carrier is equipped with enlarged "skis" to help guide it into the receiver extension. The bolt carrier's solid steel, 1-piece construction incorporates an integral piston strike face to guarantee integrity over time, while the bolt assembly is spring loaded for proper lock-up and to help reduce bolt bounce and cam pin wear. All piston components are finished in QPQ Melonite for corrosion resistance and easy cleaning/maintenance.
- Upper Receiver: A3 Flat-Top, Forged
- Barrel Length: 16"
- Barrel Contour: Government
- Barrel Material: 4150 Chrome Moly Vanadium Steel
- Muzzle Thread Pattern: 1/2"-28
- Chrome Lined: No
- Barrel Finish: QPQ Melonite / Black Nitride
- Twist Rate: 1 in 7"
- Chamber: 5.56x45mm NATO
- M4 Feed Ramps: Yes
- Muzzle Device: A2 Flash Hider
- Gas System Length: Mid, Short Stroke Piston Operated
- Gas Block Diameter: 0.750"
- Handguard: 2-Piece Polymer, Mid-Length
- Sights: None, Single Rail Gas Block
- Bolt Carrier Group Included: Yes
- Bolt Carrier Type: 1-Piece w/Integral Piston Strike Face
- Weight: 4.23 lbs
Please Note: Installation of AR-15 upper assemblies with certain features including, but not limited to: flash hiders, bayonet lugs, and threaded muzzles may violate state and/or local laws.