Mk12 Barrel- Shiny, Machined Stainless

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MK12 Barrel- Now available in Standard 18" Rifle length gas AND 16" Midlength gas and 12.5" Carbine gas! 


Due to the MK12's extended .750" profile forward of the gas block, significant marring of any paint/Cerakote/finish will occur from installation/removal of the gas block (whether pinned or set screw), no matter the finish (as the original MK12's were.)  




These are Crane Spec. MK12 barrels. These barrels are the result of tens of thousands of dollars in development done by the U.S. government to give our Special Operations guys the best weapon system they can have. We have spoken with many riflemen who have used these barrels and carried them in combat and have found unanimous satisfaction with their reliability and accuracy. Best option for long range, high precision shooting.


Material: 416R Stainless

Barrel Extension: M4 feed ramps

Chamber: Optimized for use with MK262 (Black Hills 77gr equivalent)

Twist: 1 in 7 right hand

Contour: For use with OPS Inc.

Gas Journal: .750" with gas block alignment notch for use with out .750" or MK12 tabbed gas blocks (non-tabbed gas blocks will still work)

Gas System: 18in Rifle , 16in and 14.5 Midlength, 12.5in Carbine

Lengths: 18, 16 and 12.5in and threaded 1/2x28 for use with most common muzzle devices



18in      2 lbs   6.3 oz

16in      2lbs    2.9oz

14.5in    2lbs   

12.5in   1lb    11.5oz


Gas Port:

18in      .101

16in     .076

14.5in   .076

12.5in   .077



*** We recommend gunsmith installation for all of our parts.  We cannot warranty items damaged by improper installation.

*****Centurion Arms barrels require no further break in*****


  • 5
    MK12 Barrel

    The barrel is great, but think the shining point with this experience is the customer service. Hands down the best company I've ever dealt with.

  • 5
    MK 12 BARREL

    I ordered this barrel with high expectations. As always it did not let me down. The quality was top knotch the fit and finish was everything you want from a high level barrel. Thank you for your amazing workmanship

  • 5
    Amazing Barrel and Company

    First off...Centurion Arms is a great company. Very helpful and quick to respond on any questions I had. There was an item that was misplaced during shipping and I emailed them in regards to that. Corrie responded within 15 minutes apologizing and 10 minutes after that I received tracking information and the part was delivered on my door step the next day on a Saturday.

    No for the barrel itself. It is amazing. Extremely tight fit into the upper receiver. We had to get a soft hammer and tap it into place. I do all my own hand loads, especially for the 77 grain projectiles. Out of several tests loads, I saw groups ranging from 1/2", 7/16", and 3/8" at 100 yards with different load calculations and projectile manufactures. As Bill said in a previous does not get better then that.

    I highly recommend this barrel in any MK12 build. Amazing barrel and amazing company. I look forward to ordering more products from Centurion Arms.

  • 5
    The Real Deal

    Monty and his wife, Corrie, are the real deal. I couldnt write enough to convey their integrity to you here but when you spend money with Centurion rest assured that your money is truly going to people who deserve it. Simply the best people Ive had the distinct pleasure of doing business with.
    My Mk12 barrel shoots 4 rounds in a 3/8" cluster at 100 meters on its first trip to my range. Folks, now it just dont get much better than that. The machining of the chamber is artfully done as is the outside. Its very clean and the Cerakote well executed. I also had the FSB pinned and also opted for the Ops Inc and to say Im pleased is an understatement. Its perfection and thats about all I can really say.
    Centurion Arms deserves our support.