How do you guys fix your muzzle devices?

[les_garten]

Lots of issues with Sig MPX muzzle devices in the past with accuracy. I can say that I shot mine with the new muzzle device today and it groups 1" at 25 yds. I just put a little torque on it, no measurement, just a "bit" to stick it. Shot twenty rounds to see how it did.

I was reading "somewhere" to not torque them down. Only Rockset or Lockitite and not touch for a day or two.

Anyone else do that? This is a suppressor host

 

[TonyTheTiger]

I've got plenty with quite a bit of torque to time with a crush washer, plenty that were put on almost loose but with blue loctite and a day of cure time, and some with jam nuts and minimal torque to snug it all up. No problems with any of these methods.

 

[FredHammer]

I simplified my life and run A419 Hellfires on everything. Cheaper too since you can swap them between guns. Loc-tite heat resistant on the adapter threads. #246 Loc-tite I believe.

 

[45-90]

I time them, by machining off the back of the brake, never use crush washers or jam nuts.
It stops at 11:00 ...lube first 3/4 of the thread then blue locktite the last few threads, tighten down with wrench to about 20 to 25 ft/ lbs, as brake is moved to 12:00 position.

 

[fisterofmuppets]

Over time I've bought a couple packs of Precision Armament's stainless flat timing washers. They're all in increments of 20 degrees from each other. I've used them now on several rifles and they work great to get devices timed up and torqued consistently, and they're pretty much reusable. A little more spendy than crush washers but in my experience they do everything I need them too.

 

[TonyTheTiger]

Oh yeah, forgot about the PA timing washers. Those are great.

 

[45-90]

I simplified my life and run A419 Hellfires on everything. Cheaper too since you can swap them between guns. Loc-tite heat resistant on the adapter threads. #246 Loc-tite I believe.

Area 419 are easy on, easy off, put one of their models on my 6 dasher. I like it when cleaning brakes... and adapters can be purchased for other rifles, & brake moved from rifle to rifle...but I think they are overly bulky, with too much weight except for those heavy palma, or M24 type profiles. Plus the initial cost...so I do not see me buying another. I also machine my own brakes from time to time, out of ss or titanium. Just built a 6lb 3oz AR 10 with 1 oz titanium brake...sometimes ya want to go light.

 

[les_garten]

I'm locked into the muzzle device. It is a 360 brake and requires no timing.

I'd like to mount it with just a minimal amount of torque. I cannot use any washers. It has to index on the Sig Taper.

Rockset or Loctite Red, which?

How about maybe 10# torque and the glue?

 

[msgriff]

This video does a good job of showing how muzzle device torque affects barrel constriction. How that potentially affects performance would be a different topic.

 

[les_garten]

I watched that video last night from another thread. Thanks!

 

[45-90]

The muzzle should be the tightest portion of the bore on the barrel. And a barrel is not consistent diameter throughout its length.
.0002" construction is desirable and will most likely improve accuracy. I hand lap for a slight taper and muzzle constriction at the end... I would not over tighten a muzzle device, past 30 ft/ lbs and it would depend on the amount of steel, or thickness of the barrel as to how much the diameter is diminished. This is also true for gas blocks and set screws will slightly constrict the barrel diameter, and why I choose clamp on in some instances.
Also just cutting and threading the muzzle opens up the muzzle bore diameter, so constricting it back down with torque from installing a muzzle device is probably a neutral endevor...if it's not over .0002", no big deal, the bullet will zip right through, with potential of being more accurate.
All of this has been known for many years, being discussed over 25 yrs ago in Precision Shooting with top gunsmiths of the time... including one 22 LR competition gunsmith...who used to "ring barrels" to get the right tone, to find where to cut the barrel to length for its weight, to get its full accuracy potential...he also lapped a .0002" taper in the 22 LR barrel and would not cut the outside diameter or put a set screw against the barrel OD...you can feel it from the inside when hand lapping, and you always want the tightest feel smallest by measurement...at the muzzle.