Faxon Duty Series 8" Big Gunner, 8.6 Blackout, Pistol Length, 4150, Nitride, AR-10 Barrel

(2 reviews)
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Welcome To The Future

Faxon Firearms is proud to partner with Q on the development of barrels for their revolutionary new round, 8.6 Blackout (8.6 BLK).
With barrels employing an impressive 1:3 twist rate, 8.6 BLK channels rotational energy to increase energy on-target.

Learn more about the round by Clicking Here.

As with all Faxon Barrels, these 8.6 BLK barrels are machined from raw bar stock in our greater Cincinnati Facility. Faxon 8.6 BLK barrels are fully stress-relieved, air-gauge tested, Magnetic Particle Inspected, and 11-degree target crowned to ensure superior accuracy. Constructed of 4150 CMV, each barrel goes through a battery of tests at each operation until finished in Nitride and final inspected.

All Faxon Barrels are individually checked for headspace by precision custom hardened gauges and are backed by the Faxon Lifetime Guarantee.

Consumer Note:
At the time of release, 8.6 BLK is not SAAMI certified. Please use appropriate caution while firing and when using reloaded ammunition.
Learn more and find load data provided by Q by Clicking Here.

  • Barrel Material: 4150 CMV
  • Rifling: Button
  • Barrel Caliber: 8.6 BLK
  • Barrel Twist: 1:3
  • Barrel Length: 8"
  • Barrel Profile: Big Gunner
  • Barrel Gas System: Pistol
  • Inside Finish: Salt Bath Nitride
  • Outside Finish: Salt Bath Nitride
  • Muzzle Thread: M18x1.5, tapered shoulder (adapter included)
  • Gas Block Diameter: .875"
  • Gas Block Journal Length: 1.9"
  • Barrel Extension: Standard DPMS Gen 1 .308 Extension, Black Oxide
  • Weight: 1.6 lbs
  • Magnetic Particle Inspected
  • 11° Target Crown


We have noticed inconsistencies with 8.6 BLK ammunition available on the market. Ammunition that does not match cartridge print below cannot be guaranteed to function in our rifles or barrels.


Using cartridges made specifically for semi-auto rifles may cause light primer strikes in bolt action rifles due to hard primers.


If you have any questions, please contact customerservice@faxonfirearms.com.

8.6 BLK Cartridge Drawing

Barrel Caliber:
8.6 BLK
Barrel Profile:
Big Gunner
Barrel Material:
4150 CMV
Outside Finish:
Salt Bath Nitride
Barrel Twist:
Muzzle Thread:
Gas Block Diameter:
Gas Block Journal Length:
Barrel Weight:
1.6 lbs
Barrel Length:
Barrel Length Range:
8" - 10.5"


  • 5
    Extremely solid

    Posted by James Murray on Jun 15th 2022

    The quality on these barrels is off the charts, but be warned they are not light lol. I know the weight is listed but you really can’t picture how heavy these things are until you hold one. Really hoping this round takes off because I am impressed so far.

  • 4
    Very nice

    Posted by Michael on Jun 14th 2022

    Seems to be very well made, haven't gotten to fire it yet as I am waiting on reloading dies.