How much shoulder?

[cowboybart]

How much shoulder is needed for a muzzle brake? Thinking of putting a brake on a 6mm. I'm thinking of making it 1/2-28 threads. Is a final barrel OD of .575" enough of a shoulder? .037" each side.

 

[Edd]

There are some brakes made that use the front of the muzzle as the shoulder.

 

[SSL]

Certainly no expert, but the muzzle shoulder is only a stop point. It doesn't really support anything. The crush-washer (I assume you will use one) allows timing and will rest against the 'shoulder'. Force is forward, so there is no stress against that shoulder. Remember that the crush-washer 'gives' to allow tuning the port positions and should be tightened no tighter than needed for alignment. Lots of You Tube videos on proper washer/brake adjustment.

 

[tobnpr]

the muzzle shoulder is only a stop point. It doesn't really support anything.

Actually, it most certainly does. It supports the muzzle device- having perfectly faced shoulders on both tenon and muzzle device ensures the centerline remains concentric with the bore.

Assuming there is no internal torque shoulder on the brake, if you thread a brake on and just "stop"- the brake will obviously wobble and that can't happen. Threads don't align parts- just brings them together.

That all said, for brakes (never suppressors) I've worked with minimal shoulders to make sure it's aligned properly along with Rocksett to make sure it can't vibrate loose from lack of torque. I'm not comfortable smashing a skinny shoulder with 40-50 ft lbs.

 

[cowboybart]

I won't be using a crush washer.
If 40 ft-lbs is the torque, I may need a thread locker. I'm not familiar with Rocksett, is that permanent/semi-pemanent?

 

[PatMiles]

Rocksett™

The all-purpose engineering adhesive ceramic cement. Locks, Seals & Bonds - Nuts, Screws, Shafts, Keys, Splines, Pipes, Flanges, etc. INCREDIBLE TEMPERATURE RESISTANCE (-350°F) up to 2,015°F BONDS CERAMIC, GLASS, METALS...EVEN KEYLESS SURFACES. Rocksett ideal for attaching muzzle devices...

www.flexbar.com

Details​

• Electrical insulation - for both A.C. and D.C. up to 20 Radio MHz (Mega/Hertz).
• Non-toxic - odorless - non-flammable.
• Rocksett withstands oil, fuels, acids, alkalis.
• Long shelf life.
• No mixing or priming required.
• Can only be removed by a hot water soak.
• Keeps assemblies from vibrating loose.
• Popular for muzzle brakes/recoil compensators and suppressors.

 

[SSL]

Actually, it most certainly does. It supports the muzzle device- having perfectly faced shoulders on both tenon and muzzle device ensures the centerline remains concentric with the bore.

Assuming there is no internal torque shoulder on the brake, if you thread a brake on and just "stop"- the brake will obviously wobble and that can't happen. Threads don't align parts- just brings them together.

That all said, for brakes (never suppressors) I've worked with minimal shoulders to make sure it's aligned properly along with Rocksett to make sure it can't vibrate loose from lack of torque. I'm not comfortable smashing a skinny shoulder with 40-50 ft lbs.

As I noted...I'm not an expert. I have only installed one brake on a pre-threaded barrel and followed the instructions and explanation of a tech at Aero Precision. My assembly used a crush washer and I was told specifically not to turn it too tight. Only enough to 'lock' the unit in place against the threads.
I readily bow to someone else's experience.

 

[DaveTooley]

Question
Will a suppressor be attached to this brake? If the answer is yes I would want a little bit more shoulder area. If the answer is no then you are good. I assume this isn't a semiautomatic combat rifle so Rockset is a bit of over kill. High strength Locktite will work just fine. Even blue Locktite would suffice for a hunting rifle. 40-50 ft-lbs is a lot of torque. Again if you're not going to hang a suppressor off the brake good and tight is enough. Someday you may want to take it off. Oh and use a small drop of thread locker. A little dab is all you need. Again someday you'll want to take it off.
Except for rifles that are used with suppressors all my brakes are removeable.

 

[cowboybart]

No can in the future unless they can be had w/o a Form 4. This will be for my wife's first centerfire. I can't imagine a 6/223 will have too much recoil, but while it is in the lathe, I my as well thread the muzzle.

Thanx for the link - good site