Installing a Surefire MB556k muzzle brake. Help!

[surfNshoot]

[Stockton]

Dont have written instruction but here's a step by step video:

http://www.youtube.com/watch?v=_EV1gCOJbwk

[surfNshoot]

Ahhh Haa!!! should have searched flash hider as well. Now where do I get that chart he used for indexing? I'm going to check Surefire right now.

[surfNshoot]

Don't see that chart anywhere. Anyone?

[surfNshoot]

Just called surefire. Nice customer service. They will be emailing me the indexing wheel in PDF. I will post it so others have it.

[ar15barrels]

I'll just tell you that you need to add 0.001" per 10 degrees.
Allow 20 degrees of thread crush.
Spin the muzzle device on and make an approximation of the number of degrees that is needs to BACK OFF in order to properly index.
Add 20 degrees to that figure.
Divide that degrees figure by 10,000.
Install that amount of shims.

[surfNshoot]

Thanks Randall!!! I have it indexed and ready to crush now. Of course I need the gas block on first. Will be contacting you shortly about stopping by to assemble this thing.

[X-NewYawker]

SF muzzle devices dont use crush washers. They use solid washers of different thicknesses -- you find the proper combo of washers to index the brake, then with their supplied super lock-tight you put the brake on.

[X-NewYawker]

You shouldn't be CRUSHING anything. Call CRaig in the Surefire machine shop before you ruin brake and gun: (714) 545-9444

[X-NewYawker]

I have personally installed five of these brakes on my ars and m1-As. You screw the brake on your gun -- you will see it is off a certain number of degrees -- the instruction sheet tells you the value of each washer (they are color coded) you use the combination of washers needed to index the brake, then apply glue to threads, and tighten brake down with your wrench until it is tight -- not beyond human tightening.

[PaperPuncher]

+ 1 on NO crush washer for SF brake. This is in their instructions. They should have also sent the proper indexing diagram, selection of shims, and locktite with the brake. If you do not have these items I am sure the number X-NewYawker provided will get you to the right people.

[ar15barrels]

You shouldn't be CRUSHING anything.

Did you read my instructions?

[i1800collect]

Did you read my instructions?

pretty sure x-newyawker was talking to the OP, who said this right after you gave him your instructions.

Thanks Randall!!! I have it indexed and ready to crush now. Of course I need the gas block on first. Will be contacting you shortly about stopping by to assemble this thing.

[slappomatt]

the reason they don't use a crush washer is because its made to hold a suppressor and needs to seal. Being in CA you wont be using one so a crush washer (assuming it fits) would be fine.

[ar15barrels]

the reason they don't use a crush washer is because its made to hold a suppressor and needs to seal.

Not because it needs to seal.
It uses shims because it needs to sit perfectly square on the barrel and crush washers don't guarantee squareness like shims do.

I agree that a crush washer is fine though if you don't ever mount a can on it.