I'm sure it's been discussed, but I can't find it in a search. I've seen tangential discussion of people not installing muzzle brakes correctly, and the brake/can flying downrange after a few rounds.

So, how does one correctly install a muzzle brake upon which a silencer is to be attached? Is it more complicated than... just screw it on until it's snug? How does one get it indexed properly and ensure it's lined up with the bore?

Thanks.

They come with a pack of shims of varying thickness. Use the shims to time the brake. This mean lots of trial and error.

Timing is moot, if your considering it for suppressor duty. Obviously, if you're going to use the brake w/o the suppressor then you'll want to have it indexed. A drop of Rockset will help keep the muzzle device fastened.

As above, shims and rocksett

Huh. Mine came without any shims.

I guess I'm ordering a set of shims.

Superior to shim kit but expensive out of the gate.
You can re-order single shims ($1.99) once thickness for proper timing is determined.
Each washer in the set add or subtracts 20 degrees of rotation.
Each washer has a unique notch so you don't mix them up.
Washers do not crush so timing is repeatable if removed.


 Precision Armament Accu Washer

The threads don't go all the way to the shoulder. When I screw on the brake, there's about 1.5-2mm gap between the brake and the shoulder. Am I going to need very thick shims, or what?

Is this normal?

What kind of brake is it?

They probably didn't put a thread relief in it and your barrel doesn't have one. A lot of shim sets come with one thick shim that accounts for that.

It's the SD Tactical titanium muzzle brake, with the threads for their solvent kit rear cap.

As you can see in this picture, their threads are not counterbored inside the brake, so it will need a standoff washer or a relief cut in the barrel threads (not recommended).

Why would you not recommend a thread relief for the barrel's A-class threads? This is standard practice, when threading to a shoulder.
What is a "standoff washer"? I've heard of a standoff, and I've heard of a washer, but never heard the two as a single component.

Silencer/Muzzle Device shims are usually made to match the OD of common bbl sizes. This would provide the same level of fitment as mating to the bbl's shoulder.

In all honesty, the proper way to do this (not saying anything is wrong w/ a shim kit) is to face-off the rear of the muzzle device, until the timing is correct.
It's as simple as dividing 1 by the bbl thread TPI (say 1/28), then divide this by 360* (1/28/360*), then multiplying by the amount of degrees needed to index the device (say 45*)
Example: 1/28 = .0357 , .0357/360 = .0000992 , .0000992x45 = .0045
So you'd need to remove 0.0045in, from the rear of the muzzle device, to have it indexed correctly.
This would ensure a solid fitment, to the shoulder, and ensure no extra pieces would need to be bought or could be lost.

All that math and you still didn't bore the threads out of the inside of the device.

I don't cut into barrels any more than I absolutely have to, and especially not at the muzzle. It's not standard practice, either. The TDP is for no relief on the muzzle threads.

Because you don't need to. Having a thread relief, on the A-class threads, negates the need for a start relief on the B-class.
As well as a place to end against a shoulder.
Barrel threads ran to a square shoulder a far more common than an angled one.


Been done a million times, even on pencil thin barrels. I'm not suggesting anyone reinvent the barrel thread
Besides, your relief depth is just under your minor so what exactly is so structurally unsound that this minimal dimension is the only thing holding it all together?

So you'll disassemble the gun, remove the barrel, indicate it true in the lathe, cut a relief and reassemble everything.

Instead of just cutting it in the brake. Okay.

The threads on my barrel don't go all the way up to the shoulder. There's about 1-2 mm of unthreaded, full-diameter barrel between the shoulder and where the threads begin.

I'm gonna go look at a shim kit at the local gun store, and see if it'll work.

don't forget to use an alignment rod

Darn, I've been threading the bbls before install!
Guess I've been cutting threads wrong all these years. Thanks for setting me straight

I've got my alignment rod, I've got a set of gemtech shims from the gun store, and now that I know I can install it, I'm gonna oxiclean this thing to give it a patina.

Use the thickest shim if you have a relief cut at the base of the threads, then use a combination of shims to time it until the top-center of the muzzle device stops at 11 o'clock when tightened by hand. Use a torque wrench and torque it to 12 o'clock until it is centered and you should be between 20 to 30 ft lbs. Don't use adhesives, no need for it.....just make sure that both the threads of the barrel and muzzle device are clean before installation. Install your suppressor and check for alignment.

http://www.bravocompanyusa.com/GEMTECH-Shim-Kits-for-Mounting-Flash-Hiders-1-2-x-p/gt-peelwsh-556.htm

These make life So much easier!