--- title: "Faxon Firearms ARAK-21 5.56 Black Upper Receiver" description: "Gas piston-operated 5.56 complete upper receiver with a 16\" barrel, four-position gas adjuster, dual recoil springs, and three full-length Picatinny rails." canonical_url: "https://www.kygunco.com/product/faxon-firearms-arak-21-complete-upper-recvr-5.56-16-ar-15-black" meta: author: KYGUNCO "og:description": "Gas piston-operated 5.56 complete upper receiver with a 16\" barrel, four-position gas adjuster, dual recoil springs, and three full-length Picatinny rails." "og:image": "https://cdn.kygunco.com/assets/products/269342/thumbnail.jpg?v=1731446073" "og:image:height": "500" "og:image:width": "500" "og:title": "Faxon Firearms ARAK-21 5.56 Black Upper Receiver" --- > Index of every page on this site: [llms.txt](https://www.kygunco.com/llms.txt) [Home](https://www.kygunco.com/) / [Shooting](https://www.kygunco.com/category/shooting) / [Gun Parts](https://www.kygunco.com/category/shooting/gun-parts) / [Handgun & Rifle Parts](https://www.kygunco.com/category/shooting/gun-parts/handgun-and-rifle-parts) / [Rifle Parts](https://www.kygunco.com/category/shooting/gun-parts/handgun-and-rifle-parts/rifle-parts) / [Upper Receivers](https://www.kygunco.com/category/shooting/gun-parts/handgun-and-rifle-parts/rifle-parts/upper-receivers) / FXN-URSSB556 ![Main product image](https://static.kygunco.com/cdn-cgi/image/f=auto,w=600/assets/products/269342/main.jpg?v=1731446073) For illustration purposes only, this image may not be an exact representation of the product. # FAXON FIREARMS ARAK-21 Complete Upper Recvr 5.56 16" AR-15 Black The Faxon Firearms ARAK-21 is a complete 5.56 upper receiver assembly designed to interface with a standard AR-15 lower receiver using the takedown and pivot pins. It features gas piston operation, a four-position gas adjuster, a 16" barrel, dual recoil springs, and three full-length aluminum Picatinny rails. $957.38 ** 5 interest-free payments of **$191.48** with ![Sezzle logo](https://www.kygunco.com/brands/sezzle.svg) ** ![Credova logo](https://www.kygunco.com/brands/credova.svg) As low as **$117.29**/month with ![Credova text logo](https://www.kygunco.com/brands/credova-text.svg) ** Online In Store ** Flat Rate $13.94 for every 25 lbs. Shipping to HI & AK may incur additional fees. ** Ships To Your Home Fulfilled by a partner warehouse. ** Partner Fulfilled Almost gone. Order now before it sells out. Item # 269342 Style FXN-URSSB556 UPC 816341021952 Condition New Manufacturer [Faxon Firearms](https://www.kygunco.com/brand/faxon-firearms) 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. 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. 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. **Shop with KYGUNCO for the best selection, competitive pricing, and exceptional customer service. Experience the difference that comes with buying from a trusted outdoor retailer with over 20 years of experience in the industry.** ** WARNING: This product contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to [www.p65warnings.ca.gov](https://www.p65warnings.ca.gov). 0.0 ** ** ** ** ** 0 reviews ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ** ** ** ** ** 0 ## More from Faxon Firearms ```json {"@context":"https://schema.org","@graph":[{"@id":"https://www.kygunco.com/#website","@type":"WebSite","description":"Shop KYGUNCO for firearms, ammo, accessories, parts, and outdoor gear at low prices with fast, easy nationwide shipping.","name":"KYGUNCO","url":"https://www.kygunco.com/","publisher":{"@id":"https://www.kygunco.com/#/schema/organization/kygunco"}},{"@id":"https://www.kygunco.com/product/faxon-firearms-arak-21-complete-upper-recvr-5.56-16-ar-15-black#webpage","@type":"WebPage","description":"Gas piston-operated 5.56 complete upper receiver with a 16\" barrel, four-position gas adjuster, dual recoil springs, and three full-length Picatinny rails.","name":"Faxon Firearms ARAK-21 5.56 Black Upper 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