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    • .300 Blackout

    .300 Blackout is an intermediate cartridge developed in the USA for use in the M4 carbine. The cartridge has increased performance in shorter barrels and effective subsonic performance for silencer use when compared to 5.56mm NATO. It also has superior stopping power than 5.56 NATO, especially at closer ranges, making it a suitable cartridge for many hunting and defensive applications.

    Our 300 Blackout uppers all come with a 100% satisfaction guarantee. Our complete upper receivers also come with charging handles, gas systems, bolt carrier groups, and other parts needed to complete a build for an AR platform. We also sell .300 Blackout build kits. Check them out here and if you have any questions, please reach out to our customer service team at 239-848-6757.

    • XTSCU8300BR 8.5″ 300 BO BRONZE UPPER
      Quick view

      AR-15 8.5″ 300 BO UPPER - BRONZE

      XTSCU8300BR 8.5″ 300 BO BRONZE UPPER ANCHOR HARVEY Upper Receiver 300 b/o BARREL 8″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 7″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $389.99
      $310.99
      Add to Cart
    • AR-15 8.5″ 300 BO UPPER - BLUE
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      AR-15 8.5″ 300 BO UPPER - BLUE

      XTSCU8300BL 8.5″ 300 BO BLUE UPPER ANCHOR HARVEY Upper Receiver 300 b/o BARREL 8″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 7″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $389.99
      $310.99
      Add to Cart
    • AR-15 16.5″ 300 BO UPPER - PURPLE
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      AR-15 16.5″ 300 BO UPPER - PURPLE

      XTSCU16300PP 16.5″ 300 BO PURPLE UPPER  ANCHOR HARVEY Upper Receiver 300 b/o BARREL 16.5″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 15″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $410.99
      $340.99
      Add to Cart
    • AR-15 16.5″ 300 BO UPPER - BLUE
      Quick view

      AR-15 16.5″ 300 BO UPPER - BLUE

      XTSCU16300BL 16.5″ 300 BO BLUE UPPER ANCHOR HARVEY Upper Receiver 300 b/o BARREL 16.5″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 15″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $410.99
      $340.99
      Add to Cart
    • MCS AR-15 10" 300 BO UPPER - SILVER
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      AR-15 10" 300 BO UPPER - SILVER

      AR15 300 BO upper comes FULLY ASSEMBLED. Includes: Upper Receiver 300 BO BARREL 10.5″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 9″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $399.99
      $330.99
      Add to Cart
    • MCS AR-15 8.5″ 300 BO UPPER - RED
      Quick view

      AR-15 8.5″ 300 BO UPPER - RED

      XTSCU8300RD 8.5″ 300 BO RED UPPER  ANCHOR HARVEY Upper Receiver 300 b/o BARREL 8″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 7″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $389.99
      $310.99
      Add to Cart
    • MCS AR-15 8.5″ 300 BO UPPER - PURPLE
      Quick view

      AR-15 8.5″ 300 BO UPPER - PURPLE

      XTSCU8300PP 8.5″ 300 BO PURPLE UPPER W/O BCG ANCHOR HARVEY Upper Receiver 300 b/o BARREL 8″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 7″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $389.99
      $310.99
      Add to Cart
    • MCS AR-15 16.5″ 300 BO UPPER - BLACK
      Quick view

      AR-15 16.5″ 300 BO UPPER - BLACK

      AR15 300 Blackout upper comes FULLY ASSEMBLED  with 12″ XTS Hand Guard, this will make your next build the ultimate AR. Includes: ANCHOR HARVEY Upper Receiver 300 b/o BARREL 16.5″ XTS Charging Handle XTS Forward...

      MSRP: $399.99
      $320.99
      Add to Cart
    • MCS AR-15 10.5" 300 BO UPPER - BRONZE
      Quick view

      AR-15 10.5" 300 BO UPPER - BRONZE

      AR15 300 BO upper comes FULLY ASSEMBLED. Includes: Upper Receiver 300 BO BARREL 10.5″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 9″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $410.99
      $330.99
      Add to Cart
    • MCS AR-15 16.5″ 300 BO UPPER - CE RAIL
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      AR-15 16.5″ 300 BO UPPER - CE RAIL

      XTSCU16300CE 16.5″ 300 BO CE RAIL UPPER ANCHOR HARVEY Upper Receiver 300 b/o BARREL 16.5″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 15″ M-LOK FLAT TOP RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $410.99
      $335.99
      Add to Cart
    • MCS AR-15 10.5" 300 BO UPPER - RED
      Quick view

      AR-15 10.5" 300 BO UPPER - RED

      XTS-CUBO10RD 300 BO RED UPPER Includes: Upper Receiver 300 BO BARREL 10.5″ XTS Charging Handle XTS Forward Assist XTS Ejection Port Cover 9″ M-LOK RAIL Black Gas Block Gas Tube Bird Cage Muzzle Brake

      MSRP: $399.99
      $330.99
      Add to Cart
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