Muzzle Break Timing Question

Melnibonean

Melnibonean

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I recently installed a new PWS FSC556 on my 16" AR 1 in 7 RH twist and could not get the logo to the 12 o'clock position as perfectly as I would like. It's more like (where it would be if you were looking at it from the barrel end) a 12:30 position (the little hand on a clock being the logo) or about 15 degrees off to the right or so.

Can I leave it as is, or go out and buy a crush washer instead of shims and get it dead on at 12?
 
Did it not come with a peel washer? Mine did and I had to heat an edge and peel one think layer away at a time to get it right. My other ar I used a crush washer and called it a day.

Tdc
 
Mix and match the 3 shim sizes until you get it to index at 11 o'clock hand tight, then use a wrench to bring it to 12 0'clock position, that should be roughly 30-40in/lbs. You don't need to use ALL the shims if that's what you are doing.
 
I installed a PWS PRC on a 10TR and had trouble finding the right combo of spacers. Then I found it. Getting it hand tight near the 11o'clock position is the key, a wrench will get you to top dead center.
 
If you are right handed I find timing to the 10-15 degrees to the right is perfect. Helps push rifle toward your support hand for better control.
 
A brake should be canted to 11:00 or 1:00. Not at 12.

The 858, for example, has a tab to orient the brake at that orientation.

The reason for this became apparent to me when I ran a test of a number of different brakes. I was trying to find one that reduced muzzle jump. The test consisted of firing a double tap as fast I could at an aiming mark at 25 yards. The target would show a tight group around the aiming mark (the first shots) and a big group somewhere else (the second shots).

I did this for 858s and for AR-15s. Without a brake, the second shot went about 2 feet high right.

Some brakes were so effective that the second shot went below the first shot. I found that I had to turn the brake to 1:30 to move the second shot to the left so that it was closer to the first shot.

It was then that I understood why the 858 was set to only orient a brake to the left or right.

If your brake is oriented to 1:00 and you shoot off the right shoulder, it is perfect.
 
Melnibonean said:
Can I leave it as is, or go out and buy a crush washer instead of shims and get it dead on at 12?
Click to expand...

According to PWS, they manufacture their brakes to be timed with the PWS symbol at 12 o'clock. They even have a nice short YouTube video on installing them with the shims to get the proper torque.
 
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