Image 1

ARAK-21 Upper Receiver

Lead Times Are Currently ~12 Weeks
  • Product Description

    ARAK-21® Features

    Components of the ARAK-21® Upper Receiver:

    The ARAK-21® is a gas piston actuated, complete upper receiver assembly designed to seamlessly interface with the standard AR-15 platform.  The total extent of the interface is simply the take down pin, and the pivot pin.  The new ARAK-21® upper receiver offers you all its features with no change to your current lower receiver and can be installed in less than one minute with no tools. 

    Your ARAK-21® upper receiver will be shipped to you with one “Barrel Assembly Unit” (BAU), or two, depending on which package you purchase.

    The BAU is comprised of the barrel, gas block, muzzle brake, gas piston, gas adjuster, and barrel trunnion.  The only removable part of this assembly is the gas adjuster knob.  The gas adjuster knob has 4 settings.  Three of the settings allow different gas flows for optimum operation, and one setting blocks the gas flow for a single shot operation.

    The upper receiver includes the charging block, standard charging handle, lower forearm with screws, three aluminum full length picatinny rails, three insulating shims, bolt carrier assembly, lower recoil lug with spring guide rod, and dual recoil spring system.  Along with your new ARAK-21® upper receiver you will receive your owners manual, and two allen wrenches that will fit the screws that attach the lower forearm, and the front picatinny rails.

    Due to the unique and innovative features of the ARAK-21® upper receiver, there are very few parts that are interchangeable with a standard AR-15.  The firing pin, extractor spring, and ejector spring are the only parts that are standard and interchangeable with an AR-15 upper receiver.

    Other features include:

    • The upper receiver is fully machined from an aircraft grade 6061-T6 aluminum billet in a one piece design that incorporates a full length picatinny rail (Mil-STD-1913) on the top and three additional rails on the muzzle end of the receiver, making it a full M4 style quad rail upper.  The top picatinny rail is laser engraved for optic placement.  There are also half-length picatinny rails available.
    • 12 ½” length BAU is available in 5.56, heavy profile. 16” and 20” length BAU’s are available in both the 5.56 and 300 BLK. There are two profiles to choose from, medium and heavy.  BAU’s can be interchanged in less than 3 minutes by removing the (6) captive allen screws on the bottom rail using the enclosed allen wrench.  
    • Long stroke variable setting gas piston system.  There are three options for gas flow, and one for no gas flow.  This allows for single shot operation.  There is also a clean out port for the gas block between the gas cylinder, and the barrel.
    • Charging handle is ambidextrous, non-reciprocating, foldable, spring returned and is easily relocated from left to right side without tools by the operator.

    • Model “39” Eight (8) lug bolt design with involute profile for both right and left hand versions.  The extractor is positioned at 3 o’clock.  This allows for a left hand version to use the same bolt by simply removing the cam pin and rotating 180 degrees and reinstalling the cam pin.
    • Self-contained firing pin retention system enclosed in a rectangular bolt carrier that no longer requires a cotter pin.
    • Bolted in hardened steel rail system for the bolt carrier to ride on.  This allows a metal on metal wear surface for better wear characteristics and a much smoother operation.
    • The ARAK-21® system allows for a folding stock to be added, as our recoil system does not extend beyond the upper receiver to fully operate.  This eliminates the noise and feel of the buffer tube cycling back and forth.

    PLEASE NOTE:Images shown may include items not sold with the ARAK-21® Upper Receiver.


    ARAK-21 Upper Receiver Includes:

    • ARAK-21 Upper (As Ordered)
    • Shipping Box
    • Manual
    • BAU Removal Tools
    • Magazine Marker Bands (300 BLK & 7.62x39, if ordered)
    • Bolt(s) & Firing Pin(s) for Ordered Calibers
    • Recoil Spring(s) for Ordered Calibers

    Faxon Technical Note on 7.62x39 Caliber Kit:

    • The factory recommends a high-power hammer spring to use with the 7.62x39 kit. 
    • Many aftermarket "light" triggers will not reliably ignite 7.62x39 surplus ammunition.  
    • A spring is included and installed on XRS rifles ordered with the caliber. It is sold separately for the upper or caliber kit only. 
    • Faxon offers a Wolff high power spring for sale. 
    • Faxon recommends HiperFire triggers with a special spring kit for an improved trigger pull. Contact HiperFire for details.


    • The complete rifle weighs in less than 7 lbs, with no magazine or accessories. 
    • The standard ARAK-21 upper receiver with a 16" medium barrel weights in at 5.5 lbs. Pencil barrels remove .3 lbs and heavy barrels increase the weight .3 lbs. 
    • Uppers equipped with 12.5" medium barrels weigh approximately 5 lbs. 
    • Heavy 20" barrels increase the base weight approximately .5 lbs. 

    300 BLK Compatibility:

    Due the fixed gas system length of the ARAK platform and variability of 300 BLK subsonic ammunition, a suppressor is required for reliable function with the 300 BLK BAUs using subsonic ammunition and supersonic on the 12.5" barrel. 


    Note to California Residents:

    Due to changes in California gun laws we are no longer able to sell/ship the ARAK-21 XRS to California.

  • Product Reviews


    Write A Review


      I am a US Army SOF veteran. I have used multiple weapon systems during my career. I have beed waiting for an rifle that had the best of both worlds. Finally FAXON came out with the ARAK 21! I would recommend using "Troy Industries Micro HK Style Front and Rear Folding Battle Sight". I zeroed my ARAK at 25 yards and then zeroed my red dot sight. No problem hitting targets at 300 meters! I am giving ARAK 21 5 stars!!

      on 14th Oct 2016

    2. Best ak and ar hybrid

      I love ar's but respect the durability of a ak47! This is the best of both worlds as advertised. I had a long wait to get this upper but it was well worth it. I know the DoD wants to adopt a new platform this would fit the bill! Faxon maybe you can do what colt and other gun manufacturers did with the m4 and farm out production? I'm very impressed with the fit and function of the arak21. on 13th Oct 2016

    3. precision at it's finest.

      Tolerances are tight. Recoil is smooth and flat. The ergonomics are excellent. But one now before Hillary puts a stop to it. on 13th Oct 2016

    4. ARAK21 6 month owned

      After seeing this firearm in photos for years I bit the bullet and saved for it. I purchased the upper and another barrel. Putting it on my NFA compliant lower because the barrel is 12.5" taking it out to shoot was an experience. The weapon fires smooth. Really smooth! This is my first piston driven firearm and the difference is amazing. Faxon has done a great job with their precision machining. Everything's tight and moves smoothly. With their muzzle brake the weapon is loud! All in all it's a piece of art. Only con is its kinda front heavy but I went with a heavy barrel too. Still 5 stars in my book on 8th Oct 2016

    5. Top Quality Upper

      This is the best upper I have ever used! If you want something different and more reliable than your standard AR, this is for you! Fit and finish is top notch, this upper is built like a tank! If have something wrong with your order like I had, Dominic and Pat will take care of you! I had a cracked brass deflector and they sent a replacement immediately to me. I will definitely order another ARAK-21, but this time I will order one in FDE. on 19th Sep 2016

  • Product Videos

    • Faxon Firearms ARAK 21 5.56 AR-15 AK-47 Hybrid Review (HD) ...
    • ARAK-21 XRS
      Bud’s Gun Shop:
    • Faxon Firearms ARAK 21! AR15 & AK47 Combined
      Get 10% your entire order with code "twangnbang" through Augus...
    • AR-15 - Faxon ARAK 21 - Range Review
      Shooting the Faxon ARAK-21 .300BLK upper on my AR-15 lower rec...

    Faxon Firearms ARAK 21 5.56 AR-15 AK-47 Hybrid Review (HD) Mrgunsngear Shirt link: Music by Youtube Creators & Machinima Sound
  • Find Similar Products by Category