Gunsmithing Muzzle Brake Timing

[BoltRunner]

So I had heard from some benchrest shooters that on a long range PRS or Benchrest setup that you should never run a crush washer or shim with a brake. They basically said that your putting preloaded torque on the barrel and when it heats up your POI will change. They stated that on a precision rifle that was gonna shoot over 600yds it should be brake timed directly to barrel, an AR type setup different deal as that's not a precision rifle in there mind looking for one hole groups. All my brakes are seamless done by a gunsmith so besides an AR I don't mess with crush washer timing much. I've never personally heard this so I wanted to get some other opinions, anyone that shoots 1,000 an over bolt action PRS or Benchrest seen any deviation on POI from something as small as a crush washer?

 

[Gunfighter14e2]

Yes depending other factors, muzzle device's can distort the end of the barrel but, most of the time it's a Godzilla move that does it. A crush washer that will not allow you to get timed within 30-35 degrees, you can place sand paper on flat glass an remove what you need very quickly. If you do it this way make sure you are doing figure eights. Timing the device properly is much better, but back boring the barrel is king.

 

[Belliger]

This is interesting if you think about it. Imagine if you had a brake with a shim that was torqued to 15 ft-lb. Then timed the brake and torqued to 15 ft-lb. Why would the barrel act differently enough to notice? You will certainly see a difference with different design brakes, but the same brake with and without a shim? I would need to see some data to believe that.

 

[BoltRunner]

I agree I had personally never heard of a crush washer/shim making a difference but on the same note you dont ever see anyone in PRS or Benchrest type setups running a washer/shim between barrel and brake. As Gunfighter stated either barrel is bored back or brake has some metal taken off to get correct timing so straight brake to barrel marriage is achieved. I can see some merit in a washer/shim doing something with barrel harmonics, there are tons of threads and videos on trying to achieve perfect harmonics so it might just be that it messes with this at longer distances.