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I have a Lilja barrel from the group buy and I found a brake I want to install, but it doesn't ship with a crush washer. The threading on the barrel is 5/8"x24, but the barrel dia is .740. So do I get an AR10 crush washer or the AR15 washer? I
think I need the AR10 washer, my only concern is that the ID will fit fine, but the OD will be too large. For the record the brake is
here, its 1" tapered back to .860. I just want to make sure before I order, even though I think I know the answer.
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IMO you will be better served with peel washers. Many times you only need a thousandth or two to get the break timed properly.
That's a cool looking break.
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05-07-2014, 01:19 AM
(This post was last modified: 05-07-2014, 01:28 AM by Klem.)
5/8*24 is 0.625" diameter with 24 teeth per inch.
The AR15 crush washer is;
0.5" internal diameter
0.76" Outside diameter (uncrushed).
The AR10 crush washer is;
0.625" Internal diameter
0.8" External diameter (uncrushed)
You need the AR10 washer (the AR15 won't fit). You could look into peel washers like Gunner is recommending. I use split washers for non-timed brakes like the original A1 AR's had. Split washers let you put the muzzle device on hand-tight (only) and take them off by hand afterwards to clean the crown. Muzzle devices encourage and hide the build-up of crud on the crown, and if you're OCD like me it irks you.
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DPMS 5/8 crush washers are quite large.
YHM 5/8 crush washers are smaller in outside diameter, and thus a better fit on 3/4-diameter barrels.
Shim kits are another good option for muzzle devices.
Drifter
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Thanks guys, this is the info I needed. I figured I knew what I needed, but just wanted to double check.
