MPN: JPJN-12B.750 / JPJN-12S.750


  • Re-usable
  • Easier to time your muzzle device


  • Material: Steel
  • Weight: 0.3 oz.
  • Finish: Black (Phosphate) or Raw Stainless Steel
  • Thread: 1/2"-28


  • Any barrel with 0.750" outer diameter with 1/2"-28 TPI (Threads Per Inch)


The tactical weapons community loves muzzle brakes. The problem with muzzle brakes is that most of them require correct timing to function properly and that part of the relationship can be a little strained. Crush Washers, Peel washers, and shims are all used to time and solidly mount muzzle devices to varying degrees of success. Some of them can be downright maddening when you need to remove a muzzle device. JP Enterprises offers a solution to all the hassle that those devices cause, the jam nut for muzzle brake. The JR Enterprises 1/2-28 Muzzle Jam Nut takes the hassle out of muzzle device installation and allows you to remove them with less hassle than other mounting methods.

Choose One to Match Your Build

Whether you prefer Mil-spec black or bright stainless components, JP Enterprises offers a 1/2-28 nut to work with your build. Choose your AR15 jam nut in clean stainless steel or with a magnesium phosphate finish. Either way, you get a quality muzzle jam nut that gives you an easy to time, solid mounting option for your threaded muzzle device.

Brake Installation Made Easy

Brake installation using a jam nut for muzzle brake is an easy operation. Thread the jam nut on your barrel first, then your muzzle brake. When the brake is installed at the proper timing, the jam nut should be tightened against it. The locking effect of the two parts against each other will secure the brake in place. The best part is if you change your mind, or your timing is a little bit off, you can loosen the jam nut and brake and 1/2-28 nut remove or start over and get it right without requiring an act of congress or another wait for the mailman.

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Reviews (2)

  • Locking nut

    Posted by Thomas Galdos on 17th Oct 2022

    Worked great the other nut I had was too wide and won’t let me screw the muzzle brake on very far

  • Muzzle device install made easy

    Posted by Unknown on 3rd Apr 2018

    I had 2 crush washers before and everytime I over crushed and the muzzle device wasn't sitting how it should. After getting this it now sits perfect on my AR without any hassle of timing

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