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AR-45 Complete Upper Receiver Conversion Kit (BB)

  • $949.99

Our Macon Armory AR45 complete upper receiver conversion kit with blowback upper is based on the Colt pattern and provides all you need to convert your existing AR lower into an AR45. Our barrels are black nitride coated and hand-crafted with a 1:16 twist and 5/8 x 24 muzzle thread using 4140 Chrome Molybdenum steel, providing both accuracy, durability and versatility.

Pictures do not accurately represent the current upper configuration. Blowback uppers are currently being built with Billet slick side uppers with a 3/4 ejection port door and blast deflector made to match the contours of the upper. Mlok handguards are installed and shipped with these uppers.


AR45 BB conversion kit includes:

  • Barreled upper with bolt
  • MLok free float forearm
  • Heavy buffer
  • Magazine well adapter
  • Magazine loader
  • Two magazines
  • A2 muzzle device


It is the customer's responsibility to be aware of all applicable laws and regulations regarding purchase and ownership of upper receivers with a barrel length of less than 16". Customers in NY, CA, CT, NJ, MA, MD, and CO will automatically have kits adjusted to include 10 round magazines.