Crush Washers NOT Crushing

[MegaFan]

As a word of caution, I've had two crush washer failures over the last month. I have been exclusively using Aero Precisions's VG6 Gamma and Epsilon muzzle devices, both of which include crush washers. On two recent builds using the Epsilon versions (one black and the other a bead-blasted stainless steel), the crush washers had no elastic deformation and, instead, brittle fractured. In both cases, I was trying to properly time the muzzle device when one failed at under one half of a complete rotation and the other probably closer to a three-quarter rotation. In both cases, I could tell the washer was not crushing as the amount of force/torque needed to rotate was excessive. Normally, once the initial elastic deformation starts, the effort drops slightly. In both cases, a loud pop occurred, and the fractured crush washer pieces fell to the floor. I notified Aero Precision and they were kind enough to send me four new crush washers, and they stated that they would pull a sample batch to test. Just be careful - nothing like hearing a loud pop on a brand new build when you know something gave way while you were completing an "angle of turn" torquing method. In my case, no harm, no foul, but that sudden slip of torque could have caused me to damage some other rifle part (or myself).

Luckily, I had a few spares to complete the latest build, which just happened to be a new 20-inch .224 Valkyrie on a Mega Arms billet lower, upper, handguard, trigger, with Spikes Enhanced LPK and MFT Minimalist stock.

 

[Allsmiles]

Good to know and watch out for. I normally take off the muzzle devises and just put on a thread protector for my cans. Got more than a few used crush washers and A2 birdcages in a bag.

 

[Plinker66]

I’m no expert but when I cant clock in with a crush washer without excessive force I just take it off and grind the small side down a little on my concrete garage floor by moving it in circles under the pressure of my fingertip until it is a thickness that will clock in. That works for me and it looks fine after installation.

 

[timbgtm]

The new valkyrie round is supposed to be the go round for longer range AR shooting holding up to 1500 yards before dropping out of subsonic range. I'm interested in how you like the round OP after testing.

 

[MegaFan]

I'm interested in how you like the round OP after testing.

I am anxious too, but this one is just sitting for now, with several more Mega Arms recent builds in 300 BLK and 223/556. Seems like I can find time to build but never enough time to go shoot. I will have a lot of catching up to do, and reporting, when that range day finally comes around.

 

[fast306stang]

I am anxious too, but this one is just sitting for now, with several more Mega Arms recent builds in 300 BLK and 223/556. Seems like I can find time to build but never enough time to go shoot. I will have a lot of catching up to do, and reporting, when that range day finally comes around.

don't feel bad, I have a few guns I've had for a couple of years now and haven't got to shoot any of them yet.

 

[MegaFan]

I’m no expert but when I cant clock in with a crush washer without excessive force I just take it off and grind the small side down a little...

They should always "give", allowing the actual "crush" to occur and prior to a "pop" that indicates brittle fracture. You can definitely feel when they start giving, normally, but when you can't rotate even one-half round, there is a metal grain structure issue, in my opinion. I just finished a build earlier today, and installed another VG6 Gamma with no issue. Had to rotate about 3/4 turn to time it, and I could feel the crush at about 1/2 turn, then the last 1/4 turn to properly align, just as it should have been. So far, only had an issue with crush washers shipped with the Epsilon version.