Crush Washer AR-15 Yankee Hill Machine 

Very good and educational video. I just assumed all crush washers were crap. I could not find a crush washer that would not over torque the barrel. I live close to a major AR15 manufacturer and was having a barrel pin and welded by them. When I picked up the barrel, I asked them how they get their AR15's perfectly timed without a shim? They said that they just crush it until it's timed. Made me wonder how much force they are actually applying to the barrel. Maybe they are using the YHM? Maybe they don't care? Keep up the great videos.

Is this their standard or “low profile” crush washer? Having to heavily torque crush washers to get muzzle devices oriented made me start using self tightening flash hiders and no washer whatsoever, but if YHM works like it does in the video, I may have to rethink how future builds go.

Good stuff! Brownells Colt parts do come from Colt.

Which direction should the washer face?

What type of finish is on the YHM crush washer?

Some crush washers have a nitride finish. This makes them to hard.

I know it's alleged that an overtorqued crush washer negatively affects precision, but in the 30 or so rifles I've built, this hasn't been a perceivable issue. Is there any published data suggesting otherwise? If so, how much of an effect are we talking about in terms of MOA? I'm not clear on how the mechanics of an orvertorqued washer could affect barrel harmonics in a meaningful way.