Crush Washer, Which side is toward the front or against the flash hider?
Thank You

The proper orintation of the crush washer is the concave 'dish' toward the flash suppressor, it will fit the rear circumference of the FS...


edited fer spelln...

Thank You Darkstar. I see what you mean by it fitting better that way. Thank You

Quoted: The proper orintation of the crush washer is the concave 'dish' toward the flash suppressor, it will fit the rear circumference of the FS... edited fer spelln...

I tried that.  Wouldn't crush down at all.  I couldn't turn it more than 5 degrees.

I turned it around and put the dished part toward the barrel shoulder, and it fit better, and crushed just fine.

Is there any 'official' build info/manuals that show which end pointing where?

The "smaller" end that contacts metal is meant to touch the barrel.  The wider mouth contacts the device being installed (e.g. suppressor, muzzle brake, etc)

mark
[email protected]

While all the above is correct (wider part of crush washer against the wider part (FS), I have seen them come factory assembled both ways...

Personally, I like the more streamlined look of the "correct" way.

When I sent my barrel out to get a Phantom permanently installed, it came back with the wide part of the crush washer towards the barrel.  It doesn't really bother me, but I was expecting it to be installed the "correct" way.

I asked Bushmaster to deliver the 24" NM Heavy-barrel ASSEMBLY with the A2 birdcage installed... well it arrived and I found the A2 birdcage plus this weird washer (looked concave/convex depending on how you look at it).

My machining/engineering experience tells me that this is a crush washer. The tapered/sharp part of the washer would most likely "chew" into the metal as it was being crushed.

I figured that it was cheaper and easier to replace the flash hider if it was excessively "chewed" out by the washer in a worst case scenario, rather than replace the barrel.

So what I did was slip the washer with the flat side facing the barrel meat, and hand tighten the birdcage until it was flush. I then used the USGI barrel wrench and timed the flash hider so that the bottom did not have any slots (all facing up). I didn't bother with a torque wrench.

Did I do this right? I know the crush washer orientation is being debated here, but did I do everything else right?

Sounds good, but you don't have to worry about the crush washer damaging either the barrel or the flash hider.  It's made of a much softer metal than the steel of those parts.