Accu-Washer® Muzzle Device Alignment System

(23 reviews)
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Simply choose the correct size Accu-Washer® shim to accurately index your muzzle brake or flash suppressor while maintaining perfect bore alignment. Since only one shim is required, the tolerance stackups and complexities associated with peel washers and other multi-shim systems are eliminated. This minimizes the risk of baffle strikes, ensuring maximum accuracy and safety from your muzzle brake or suppressor.

  • Includes 18 individually marked Accu-Washer™ shims (timing adjustable from 0-360 degrees in 20-deg increments) and easy to follow instructions.
  • Precision machined from high strength 400 series stainless steel to a guaranteed thickness uniformity of ±0.0001".
  • All shims feature an oxide blasted non-reflective surface finish for low visibility.
  • Each shim is chamfered on one side to allow clearance for barrels with radiused thread shoulders.
  • One Accu-Washer System will align approximately nine brakes (on average) before replenishment shims are needed.
  • Designed to fit 1/2x28 or 5/8x24 threaded barrels.

Note: The Accu-Washer Alignment System can be used with any brand muzzle device.


  1/2x28 5/8x24
O.D.: 0.750" 0.825"
Thickness: 0.060"-0.094" 0.060"-0.100"
Full Spec Sheet: View PDF
Installation Manual: View PDF


Accu-Washer shim with chamfered edge

Shims are individually marked for easy identification


Accu-Washer shim with chamfered edge

Each shim is chamfered on one side to allow clearance for barrels with radiused thread shoulders


We recommend these for installing our:
M4-72 Severe-Duty Compensator
M11 Severe-Duty Muzzle Brake
M11-SPR Severe-Duty Muzzle Brake
EFAB (Enhanced Flash Arresting Brake)
AFAB (Advanced Flash Arresting Brake)




Crush washers are perfectly acceptable to use on any open aperture muzzle device, such as the standard A2 birdcage flash hider. However, our opinion is they should never be used on any baffle style muzzle device where the clearance hole is only slightly larger than the bullet. Firstly, crush washers come to a knife edge on both mating surfaces - it is likely for this reason that a muzzle device is already misaligned just sitting on the crush washer before it is even torqued down. More importantly, it relies on the principle that the washer will deform uniformly while it is being crushed. This requires that the material is uniform and that you apply a perfectly pure torque load normal to the bore. This is very unlikely (for anyone who has installed one) when you're putting all your might into the 30-60 ft-lbs of torque they often require. The consequence of this misalignment is a baffle strike causing bodily harm at worse and impaired accuracy at best.

On average, each pack will get you about 9 installations before a single replenishment shim is needed. Instead of increasing the price on all muzzle devices to include the Accu-Washer Alignment System, it makes more sense for a user to buy one pack separately and use it across multiple installations.

First, make sure the threads on your barrel and muzzle device are completely clean and free of all debris. Any contamination can limit the rotation. Next, applying a moly-grease or CLP-type lubricant to the threads on the brake and barrel will provide further rotation for the same torque. We suggest you apply generously, then run the brake on and off the barrel a couple times to work it in, then wipe up any excess. The coefficient of friction between the threads is what limits your rotation, cutting this coefficient in half with grease can give you twice as much rotation. You may also apply some lubricant to each side of the shim as there is friction in the works here too. Lastly, a little elbow grease. Since the Accu-Washer shims are used to adjust your brake in discrete intervals, it is inherent that the torque required for proper alignment will fall in a range. The torque load specified in the instructions is merely the minimum required so your device does not rattle free, however you will need to continue to apply torque beyond this to achieve alignment. Higher torque installs may require holding the rifle in a barrel vise.



For full specifications, installation manuals, and more - visit our Technical Resources page:


  • 4
    alignment system

    Posted by john on 7th Jun 2024

    works as they should would be nice if they were offered in stainless steel and blued

  • 5
    Accu-Washer shims

    Posted by STACE on 31st May 2024

    These are my go to shims. They give you the ability to time any muzzle device. The quality is excellent. Over a dozen installed, never a baffle strike.

  • 5
    Best alignment system going

    Posted by Gregdr01 on 2nd Dec 2023

    I look at my life before, and after, this muzzle alignment system. Before, I did nothing but struggle with various configurations of shims, trying to properly time my muzzle devices. And when I did finally get one right, it'd never go back on exactly the same after removing for cleaning. Now, all I ever need is one properly-sized washer, which is a breeze getting right on the first or second try. Better yet, time and again the device goes off and back on, spot-on timing. I'm on my second set, plus a few additional one-offs. Just wish I'd found this product years ago!

  • 5

    Posted by David on 12th Oct 2023

    Way easy to use. Directions are perfect.

  • 5
    Spacer for Muzzle Brake

    Posted by Jim Morlan on 4th Oct 2023

    Excellent fit. And super fast shipping. Great company.

  • 5
    Spacer for Muzzle Brake

    Posted by Jim Morlan on 29th Sep 2023

    Fit perfectly. Didn't want to use a crush washer. And this did the trick. Amazing customer service. Even called to make sure I was getting what I needed. Amazing company. Definitely recommend them. And there produces.

  • 4
    Accu washers

    Posted by Kevin Collins II on 18th Sep 2023

    I used it on my stag tac15 woth the precision armament EFAB muzzle device and I found the exactly right washer for the perfect tight fit. So far it's been a great product.

  • 5
    Great product

    Posted by Lavar Bowles on 14th Sep 2023

    Had all the washers I needed to time the muzzle brake.

  • 5
    Great Kit

    Posted by Eben M Atwater on 14th Sep 2023

    Well worth the price - perfect fit every time for alignment critical brakes