2A Armament Builder Series Complete AR-15 Upper Receiver .300 Blackout - 8"

Manufactured by 2A Armament
Manufactured by 2A Armament
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Note: Barrel length is less than 16” and must be attached to a pistol lower or registered SBR lower. All NFA and local laws and regulations apply.

2A Armament's Builder Series was designed to provide your next build with rugged, lightweight, reliable, and best of all affordable components. The Builder Series complete upper receivers are no different. These flat-top, optics ready receivers feature the Builders Series free float M-LOK handguards machined from genuine USA certified 6061 aluminum extrusions with full length top-rails and three tracks of M-LOK slots to provide plenty of space for your favorite accessories. The upper receiver is from the Palouse-Lite series that are forged from 7075-T6 aluminum with a lightweight slick side design without forward assist. Even better, these uppers are ready to roll from the factory, simply add your favorite sights, drop it on a complete lower and hit the range!

  • 8” barrel chambered in .300 Blackout
  • 4150 CMV barrel made by ballistic advantage
  • 1:7 twist rate and 5/8x24 threads
  • Low profile .750” steel gas block
  • X3 compensator
  • M16 bolt carrier group Nitride finished
  • 9310 bolt MPI
  • Palouse-Lite 7075-T6 forge aluminum receiver
  • Free float M-LOK handguard
  • BCM-Mod4b ambidextrous charging handle
  • Weight: 2lb. 13 oz.

The 8” 300 BLK barrel is made by Ballistic Advantage out of 4150 CrMoV steel with a 1:7 twist rate optimized for heavier ammunition. Attached to the 5/8x24 threads is the X3 compensator to reduce felt recoil. The bolt carrier group is high quality as well with the carrier being made from 8620 steel and the bolt being made from 9310 steel and then Nitride finished. Additionally, it is magnetic particle inspected to ensure quality machining. This complete upper receiver group also features a BCM-Mod4b ambidextrous charging handle.

2A Armament is not just another firearms manufacturer. They are committed to exceptional craftsmanship and quality in the products they make. State of the art manufacturing paired with hand finishing of every part result in firearms with unmatched fit and finish.
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AssemblyComplete Assemblies
Barrel ContourBA Hanson
Barrel Length8.0
Barrel Material41V50 Chrome Moly Vanadium Steel
Brand2A Armament
Caliber Gauge300 Blackout
Gas System LengthPistol
Gas System TypeDirect Impingement
Muzzle DeviceX3 Compensator
Twist Rate1:7
Weight2 lbs. 13 oz.

WARNING: This Product can expose you to chemicals which is known to state of California to cause Cancer and Reproductive Harm. For more information, see www.p65warnings.ca.gov

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