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AR-45 Complete Upper Receiver Conversion Kit (BB)

  • $899.99

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.

NOTE: The 5 inch barrel conversion kit uppers come without a forearm as most customers prefer to pick their own for the 5 inch upper. We have a limited amount of short Quad rails for the 5 iinch in stock, Call us!


AR45 BB conversion kit includes:

  • Barreled upper with bolt
  • KeyMod free float forearm
  • Heavy buffer
  • Magazine well adapter
  • Magazine loader
  • Two 20-round magazines
  • A2 flash suppressor


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.