17-5.56 KAK Complete AR15 Upper, 18" Barrel, 15" Mlok

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  • Barrel Length-18”
  • Barrel Material- 416 R Stainless, Blasted Matte Grey
  • Chamber 17-556 KAK
  • Twist Rate 1:9
  • Muzzle Device- KAK SAW Flash Hider 
  • Extension- M4
  • Gas System- Rifle Length
  • Gas Block- Low profile .750 Phosphate Finish
  • Upper Receiver- Forged 7075 T6 Aluminum, Precision Machined to M16/M4 Spec
  • Handguard- 15” Mlok, High Quality 6061 T6 Material Mlok with Proprietary Clamping System and Heavy-Duty Barrel Nut
  • Charging Handle- Milspec with Enhanced Large Billet Latch


  • M16 Auto Profile Carrier Machined from Aircraft/ Bearing Quality 8620 Steel, Properly Heat Treated, Ground to Perfection
  • Bolt is machined from a single piece aircraft/bearing quality 9310 steel, heat treated properly, precision ground, Shot Peened and MPI’d
  • Firing pin is machined to the mil-spec print 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
  • KAK Carrier Key Screws- T25 drive, Grade 8, Properly Heat Treated

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

NOTICE- 17-556 Was created by KAK Industry and is our proprietary chamber design. This chambering is NOT cross compatible with similar cartridges, do not attempt using other rounds in the 17-556 chamber.

Cases we are being asked about regarding cross compatibility are too long, if you manage to jam the neck into the throat the headspace is almost .100 short so you're risking a catastrophic failure, don't shoot ammo in guns it's not chambered for.

This chamber is NOT compatible with 17 Remington




  • 5

    Posted by Michael on May 19, 2024

    I bought this upper a couple months ago and have held off writing a review until I ran it through its paces for awhile. I'm very pleased with it. It absolutely drives tacks and is a blast to shoot.