BCM Comp Installation

[ssc]

Was involved in a bit of conversation at the range regarding installing a BCM comp. The issue could be changing any muzzle device. Some folks position was to remove the MD and then clean threads and install dry. Others felt that some oil on the threads was the correct method. Others claimed that anti-seize should be applied to the threads prior to install.

So I figured I would ask here about the correct method. How do you prepare the muzzle threads when installing a new MD?

Cheers, Steve

[Randall]

I always clean and degrease the threads of both the barrel and the muzzle device. For a BCM comp I would reinstall it with a new crush washer, and a little anti-seize if you want (I never have). I wouldn't use oil.

For anything that needs shimmed and timed I do a test run until I have the correct shims and am timed correctly. I then break it apart, apply Roksett, and torque again until timed perfect.

My torquing method is as follows:

-Set torque wrench to 20 ft/lbs.
-Test the timing with the shims I think I need and torque until it clicks. If over timed, add more shims and repeat torque at 20 ft/lbs.
-Once 20 ft/lbs is met with the MD slightly under timed, set wrench to 30 ft/lbs.
-Torque until timed.
-Break apart, apply Roksett, torque again until timed.

This method should ensure you always hit 20 ft/lbs minimum, and never go over 30 ft/lbs maximum. I realize with a BCM comp, a crush washer doesn't have a torque value, but I figured I would give my method for both since you kind of left it open to other MD's as well.

[Swstock]

I use the supplied crush washer and 33ms.

[markm]

Clean & dry as possible for me.

[mpom]

No expert here, but adding anything such as anti seize will reduce the torque required to reach given alignment, as the anti seize acts like a lubricant. Dry torques setting should be reduced if using anti seize.
I personally use a high heat resistant low yield thread locker and low torque, for maximum accuracy and reassurance that device will not loosen on its own.

Mark

[mark5pt56]

Don't overthink a crush washer. Clean the threads, place washer on, thread MD by hand until it stops. Look at the top dead center of the MD, minimum 1/4, max 1 1/4 turn to TDC of barrel, no torque.

[georgeib]

Don't overthink a crush washer. Clean the threads, place washer on, thread MD by hand until it stops. Look at the top dead center of the MD, minimum 1/4, max 1 1/4 turn to TDC of barrel, no torque.

This.

[ssc]

Don't overthink a crush washer. Clean the threads, place washer on, thread MD by hand until it stops. Look at the top dead center of the MD, minimum 1/4, max 1 1/4 turn to TDC of barrel, no torque.

Thanks for the responses. The above is how I do it. However, it sure brought out some discussion.

Cheers, Steve