Crush washer question

AR/M4 Custom Build Forum
1

I’ve decided to install a Larue rail on my upper receiver group myself rather than taking it to a gunsmith. In order to install the rail, I’ll need to remove the FSB from the barrel, which in turn will require me to remove the flash hider.

Do I need to use a new crush washer when re-installing the flash hider? And how tight should I torque the flash hider when re-installing? The Army/Air Force Technical Manual says 15-20 ft-lbs, but it assumes I’m using a peel washer, not a crush washer.

Thanks for your help.

2

I’ve read on the internuts that you can’t reuse the Crush washer at least on the same indexing. It makes sense that it wouldn’t work unless you slightly over timed the FH.

I’d take the opportunity to replace the crush washer with a peel washer.

3

There is no torque value for the crush washer. You tighten the washer until it is tight and ensure that it is TDC of the center of the front sight base. I also do not recommend re-using it. Buy a new and do it right.