Timing a muzzle brake

[CjC73]

Purchased a couple and on one rifle it screws on easily and is only off by about 10deg(?) past where it would be lined up perfectly. It's not much at all. But enough to annoy me and my engineer OCD. So what's the best way to back it off?

Other rifle is a different story. Brake screws on hard the whole way and stops completely with about 0.300" gap. See picture.

So....what would be the best option for this situation?

Thanks for all your help

 

[cohunt]

Have the brake timed by a Smith or machinist --- or try a shim

 

[ar10ar15man]

shims are common
not a big deal
thunderbeast sell some peal washer shim

 

[lancetkenyon]

Gunsmith. I like my brakes to blend seamlessly with the barrel too.

 

[yorke-1]

If you're concerned about aesthetics, bring it to a smith, otherwise the shims work well.

For the brake that doesn't screw on all the way I think the only real solution would be to reduce to the major diameter of the thread on the barrel (or brake). I've had this issue before when the threads were cut by different people. You may even get away with just taking some emery cloth and knocking down the very edges of the muzzle threads. They probably only need to be reduced by a couple thousandths.

 

[Daveog]

I agree with all the above statements. Not all brakes are designed to blend perfectly to the barrel, and so shims are expected. The AR platforms almost all use a crush washer or a similar device to align the flash suppressor. The Surefire brakes all come with washers of varying thickness and a chart to help the end user time them.

For the other one, a gunsmith is your best bet. It sounds like one or the other threads (barrel or brake) were threaded to closely to "perfection" without any room for variation. You could try to get a tap of appropriate size and run it through the brake. That may open it enough to allow it to thread fully if that is the problem. I wouldn't try anything on the barrel side though because that is a much more difficult problem to solve should it get messed up.

 

[TheLongRanger83702]

Crush washers.

 

[ntsqd]

For the first brake you'll need to either shim it or carefully shorten it until it will go on almost one full thread further. For that to work there needs to be enough thread inside the brake for that to happen. If shimming it is the desired method and the thread size works then look into the peel washers that used to be used on AR flash-hiders before the aftermarket got lazy and mislabeled a Belleville spring as a "crush washer".
If shortening it is the desired method and you don't want to take it to a smith then you may be able to do so with a drill press and a LOT of care. Chuck up the brake and spin it against an abrasive sheet on the table. This will be time consuming and laborious, but it can work with care. Do Not bear down hard of you will distort the table and affect your fit.

For the second brake you need to know it is the thread fit or the thread depth that is causing the problem. If the former then taking down the OD of the barrel threads may work. If they are badly off from the brake threads then a much more involved approach is needed and I think it's time for a smith or at least a journeyman machinist with access to high tolerance tooling. If the latter then the brake needs to be examined for if the threads can made deeper. If they can not then you're looking at shortening the barrel threads or a spacer-shim.

 

[Jeffpatton00]

I've found the Accu-Washer system from Precision Armaments useful, not too expensive and it gives plenty of options for timing a brake. Here's an example in .308:

https://www.brownells.com/rifle-par...lver-sku100010537-98457-105319.aspx?rrec=true

 

[skipglo]

Purchased a couple and on one rifle it screws on easily and is only off by about 10deg(?) past where it would be lined up perfectly. It's not much at all. But enough to annoy me and my engineer OCD. So what's the best way to back it off?

Other rifle is a different story. Brake screws on hard the whole way and stops completely with about 0.300" gap. See picture.
View attachment 136287
So....what would be the best option for this situation?

Thanks for all your help

Buy a Crush Washer...it's what they are made for and work great. Tapered side goes to barrel not the brake

 

[ntsqd]

That is a peel washer and a good find

I've found the Accu-Washer system from Precision Armaments useful, not too expensive and it gives plenty of options for timing a brake. Here's an example in .308:

https://www.brownells.com/rifle-par...lver-sku100010537-98457-105319.aspx?rrec=true

Actually those are a Belleville spring and they're made to do a lot of different things. Firearms marketers have mislabeled them. https://www.mcmaster.com/metal-belleville-spring-washers

Buy a Crush Washer...it's what they are made for and work great. Tapered side goes to barrel not the brake

 

[DSheetz]

You can get bottom taps to cut the internal threads on the brake and clean them up you also can get a die nut to clean up the external threads on your barrel they should be easily turned and not take much metal off use a good cutting type of oil to lubricate the threads when doing this . I ground the end of my tap so that the threads on it will cut to the bottom of the hole even though it has a relief cut into it to allow it to be screwed all the way on as should the threads on your barrel . I put the tap in my vice and use a brass rod in the holes to screw the brake onto it . I put it in my lathe and turn it down on a tapper to the out side dimension of my barrel

 

[skipglo]

Buy a Crush Washer...it's what they are made for and work great. Tapered side goes to barrel not the brake

Purchased a couple and on one rifle it screws on easily and is only off by about 10deg(?) past where it would be lined up perfectly. It's not much at all. But enough to annoy me and my engineer OCD. So what's the best way to back it off?

Other rifle is a different story. Brake screws on hard the whole way and stops completely with about 0.300" gap. See picture.
View attachment 136287
So....what would be the best option for this situation?

Thanks for all your help

If you can't find the crush washer readily let me know and I can mail you one or two...I have a couple extra!

 

[skipglo]

If you have a 30 call break tap is 5/8 x 24 thread.. if 223 generally 1/2 x 28 tpi...

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