Crazy muzzle device installation - what?

[Shao]

So I volunteer to swap out my buddy's birdcage on his AR pistol with a KVP linear comp. I pop his old A2 off - no problem there - install the crush washer (flared end towards the muzzle), gently thread the KVP onto his barrel, put the barrel in the vice jaws, and with a small hand wrench (I never use a large armorer's tool for this task to reduce the chance of over-torque), I start backing the KVP onto to the crush washer. It seemed to thread on entirely too easily, I backed off little by little before retightening, but it just went on and indexed like butter. It's tight - perfect - I didn't have to bear down at all on the little wrench - but look at this crush washer:



I grabbed a random crush washer from my tool kit which must have either been a Brownells or PSA - has anyone seen one flare up like this??? I've installed a few muzzle devices and never seen one do this. The ease of installation is also puzzling. Maybe the crush washer is made of some kind of softer steel??

Has anyone seen anything like this except for on overtorqued barrels???

[MistWolf]

Crush washers are inconsistent. Some take more torque than others and is another reason I've stopped using them

[Shao]

Crush washers are inconsistent. Some take more torque than others and is another reason I've stopped using them

Thanks for the insight. On my last personal build, the brake was a Hera Arms linear comp and, luckily, it indexed perfectly with an A1 lock washer (so installation was a breeze). Now I'm starting to seriously second guess crush washers myself.

EDIT: Just had a thought that made a lot of sense.... Maybe it's the shape of the comp? No shoulder - it tapers down to a point where it nestles into the cup side of the crush washer - maybe that's why it was so easy to install and flared the washer like it did?

[MistWolf]

That would do it too. The taper becomes a wedge

[Shao]

That would do it too. The taper becomes a wedge

That's the leading theory for now - now can anyone with a KVP linear comp chime in and let me know if you had a similar experience with your install?

[bruin]

Is there a reason you need a crush washer at all? I thought linear comps don't need to be timed.

[Shao]

Is there a reason you need a crush washer at all? I thought linear comps don't need to be timed.

Well I wanted the flats to be even for aesthetic purposes - plus doesn't a crush washer add backwards pressure to your muzzle device, keeping it locked on tighter than one without??

[MistWolf]

On many muzzle devices, the threads will bottom out before meeting the shoulder.

Using a crush washer, peel washer or a shim will protect the barrel shoulder from being damaged from the muzzle device turning against it directly

[Shao]

On many muzzle devices, the threads will bottom out before meeting the shoulder.

Using a crush washer, peel washer or a shim will protect the barrel shoulder from being damaged from the muzzle device turning against it directly

Ahh.. that's right.. You're exactly right. I'm not worried about it because it's indexed perfectly, went on like a dream, and seems rock solid. I was just concerned about how the crush washer looks. I've never seen one so... flared....

EDIT: I could have probably gone another full revolution with the wrench, it turned that easily - I just snugged it to the point that it couldn't be undone by hand and was indexed to be purty.

[Voodoo_Man]

swivel wrench or however you call it works.