Adco Firearms on Caution with Nitride Finishes

Adco Firearms, well known for their AR-15 gunsmithing services, recently share the image below along with the following words of caution for dealing with nitride finished barrels…

adco firearms nitride barrel caution

Black Nitride is a good surface hardening technique, but it also makes things brittle. When timing a flash hider to a 1/2×28 threaded 9mm barrel, don’t use a breaker bar to try an get one more rotation. It will snap off like glass.

This is probably a good reason to use a timing shim set instead of a crush washer on nitride finished barrels. The timing shims will allow you to time the muzzle device without putting as much stress on the barrel which will prevent the above and have less negative effect on accuracy.

4 Responses to Adco Firearms on Caution with Nitride Finishes

  1. comradewhoopie January 13, 2016 at 10:54 #

    Forget the crush washer, use Locktite blue or epoxy. Both can be ‘broken’ by gentle heating with a torch if you ever need to remove the flash hider/muzzle brake. Besides, over torquing can distort the muzzle causing inaccuracy. I had that problem with a pre-ban Colt AR-15. Undoing the tight A2 flash hider and replacing it with locktite significantly improved groups.

    • Matt January 13, 2016 at 11:00 #

      I don’t use crush washers any more either. I use timing shims and torque to 15-20 pounds. Threadlocker generally isn’t necessary but, like you say, a little of the blue type probably couldn’t hurt.

      If you are going to use a crush washer, remember to crush it a little at a time. Apply torque and then back it off. Apply torque and then back it off. Repeat until you can time the muzzle device without exceeding the torque spec.

  2. Jon January 14, 2016 at 05:20 #

    How much torque was truly involved? Was the barrel properly processed? So many variables here that are not accounted for…

    • Matt January 14, 2016 at 07:46 #

      Agree. That is why no one is saying don’t use nitride processed barrels. I would say a breaker bar shouldn’t be needed to time a muzzle device regardless of the finish. But, I am glad ADCO put the image out there as a public service.

Powered by WordPress. Designed by Woo Themes