KAK Complete AR15 Upper Receiver - 9mm - 4" Barrel - 5.5" MLOK

(2 reviews)
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  • Barrel Length- 4”
  • Barrel Material- 41V50 Button Rifled Barrel
  • Chamber 9MM NATO
  • Twist Rate 1:10
  • Muzzle Device- KAK Flashcan 1/2-36
  • Gas System- Blowback 
  • Upper Receiver- Forged 7075 T6 Aluminum, Precision Machined to M16/M4 Spec
  • Handguard- 5.5”, High Quality 6061 T6 Material Mlok with Proprietary Clamping System and Heavy-Duty Barrel Nut
  • Charging Handle- Milspec with Enhanced Large Billet Latch
  • BCG
  • One piece BCG
  • Auto Profile Carrier Machined from Aircraft/ Bearing Quality 8620 Steel, Properly Heat Treated, Ground to Perfection, BlackNitride Finish by H&M
  • Firing pin is machined from 8740, precision ground, and chrome plated
  • One Piece Billet Fully Machined Enhanced Extractor, Phosphate coated for Increased reliability and corrosion resistance
  • S7 tool steel ejector and extractor retaining pin
  • 4130 Gas Key, nitride, precision staked using our hydraulic staking machine
  • Carrier key screws- Grade 8, Properly Heat Treated and staked

All KAK complete upper receivers are test fired for feed and function using commercially loaded ammunition



  • 5
    KAK 9mm upper 4“ complete

    Posted by Shawn Miles on January 29, 2024

    Love the product. Built very well and the price is right. Wish there was a less bolt option as I use other BCG’s. Fast shipping.

  • 5
    Kak 9mm pistol upper

    Posted by Bill Kirkland on January 19, 2024

    I just had to take a little of the back of the ejector to get it to run flawlessly with my KAK pistol lower