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Posted: 4/17/2007 4:06:47 AM EDT
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With what torque should one install a birdcage flash hider onto an A1 11.5" upper? Thanks in advance. |
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For an A2 bird cage or similar put your crush washer on then hand tighten until tight. then wrench and "crush the washer" until you are "timed" like the face of a clock until the flash hider closed ports are at the 6 o'clock position. A crush washer is set up for (I believe) two revolutions of crushing (maybe more). This is also why you can only use them once. For an A1 type just wrench it until you have around 30 ft lbs. But I am guessing on that so wait for clarification. |
Some flash hiders are designed to work in a specific orientation. For example, with an A2 flash hider the solid area should be on the bottom. Hence the FH must be indexed so that this is the case. There is no specific torque when using the crush washer. The whole idea is to have a washer that provides an acceptable level of friction over a wide range of rotation, so that the hider can be placed in the acceptable orientation. |
| I've been thinking that I want to install a FH or comp without torque on the barrel. Believe I can time the FH by sanding the end on wet/dry sandpaper on glass base until threads line up. Then secure with red locktite. Firearm intended to punish paper only. Would this be really stupid, or just moderately so? |
You'd probably be better of using a peel washer. Instead of sanding your FH, you just peel layers of the washer off until you can index your FH w/ as little torque as you like. The layers of the peel washer are thousandths of an inch. I'm not overly certain just how thin/thick they are but, I prefer the peel washers so I can index them myself w/o going overboard on torque or having a FH I'm not certain is tight enough. HTH- Sly |
No, I use a peel washer to properly index the FH while ensuring I apply enough torque to satisfy myself that the FH is on tight w/o applying too much torque. If you want to set yours up w/o much (if any) torque applied to the barrel- you may wish to apply locktite to ensure it doesn't loosen... As I rarely use loctite, I'll pass on the opportunity to throw in my two bits as to the suitability of loctite on a FH. Perhaps there's someone w/ more experience concerning loctite out there because I must admit my knowledge concerning the use of loctite is minimal at best. Sly |
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You did it right. |
I used peel washers to get "hand tight" only on a Denny's RECON barrel and then added red loctite to hold it in place. When I removed the FS a few hundred rounds later, the red loctite was still there, but it had been reduced to more of a friction additive like the red dot on an A2 buttstock screw. It was worth doing IMHO to maintain the awesome accuracy of the Denny's Recon bbl. |
Just get a Vortex. Hand tighten and that is all....it will tighten itself to where it needds to go. |
Thanks, everyone, that was extremely helpful. And raises good points concerning other issues I need to explore and learn. |
That would really be stupid. It would be easier to use the correct parts. |
Maybe i dont underatand you. He is using using the correct parts. He just doesnt want to torque his barrel, sound good to me, but what do i know ive only instaled like 7500 flashhiders. 
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I think it's 1/2 a turn minimum and 1.5 turns maximum in order to index with a crush washer. There is most certainly NOT a full 2 revolutions of crush (0.070") engineered into the crush washer. |
So what tricks do you use to check the alignment? I thought AtlantaFireman had a neat idea in his Blackthorne thread!  Anybody else use the Popsicle stick test? 
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Ok so uhhh I did this at home last night. I don't have a vise. That should have been my 1st reason to stop. So here's the deal, do you folks use a LOOOOOOONG as wrench when screwing on these damn things? I mean HOLY HELL with just my foot and some huevos it's a BITCH to screw that thing on there. 1.5 turns my ass! Maybe a .6 turn! 
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Yeah.... it's bothering the ever lovin' shit out of me. I'm using that Popsicle trick to check my "timing" and the TIME IS OFF BABY. By just a few degrees, but enough to drive my perfectionist mind bananas. Problem is, 1 I NEED A DAMN VISE. Not this foot on the floor poor man technique. Secondly I need the correct size wrench and not an adjustable one.  (confession time: I'm certain I also put the crush washer on backwards because there was just no way it was going to crush the other way I had it) 
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Take the popsicle stick out and forget it. The M16A2 technical manual allows for several degrees of +/- in timing the A2 Flash hider. I think a little bit off of TDC is hardcore and proof that you're not KNS pin using geek! 
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I've stoned every crush washer I've had in order to get proper timing. I really don't like going over 30ft-lbs on a muzzle device. I've got one flash suppressor that looks like it was installed with way too much torque. (It wasn't installed by me.) It took a lot of force to remove even after I broke it loose. It didn't look cross threaded or anything. Then when I re-attached it, it took a lot of force to apply. Enough so that the flash suppressor was creating enough friction to get too hot to touch. My guess was that it was torqued WAY too much and the threads got distorted. 
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Well I'd venture a guess I went just a tad over a 90 degree turn. But that was with a backwards crush washer. did I mention I used my foot?God I suck. |
| I'm just a new guys to AR's but here is how I timed my flash hider with out to much torque. I installed my crush washer and then treaded on my flash hider. I would then see how close or how far off the timing was. I then removed the flash hider and crush washer and taped the washer to the end of a hammer. I then hit the washer on a piece of steel with the amount of force I felt was needed. Then I would install the washer and flash hider and see how close I was. This way I could get the flash hider really close and only have to put a slight amount of torque on the barrel to install it. I finally got sick and tired of messing with timing flash hiders and bought Vortexes for my AR's. |
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I am a bit confused about alignment now that I have seen a couple 6920's (?) a leo friend had. The A2's that were on them were aligned so that the middle of the solid area was at about 8 o'clock or so (when looking at them from the front). Both were factory guns. He said it was because when firing the guns wants to rise up and left and the direction of the ports helps direct it down and right. |
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This is a good thread... I need to get a phantom 5c2 indexed correctly on my xcr... Here is where is is now:  The wide section needs to go all the way around to the bottom... I don't have a vice, and trying to turn the bastage with a wrench is extremely awkward, and I'm in danger of dropping a damn nut every time I try... Stickman recommended crushing the washer a little in a vice-which I dont have so that's out, and I was thinking to myself earlier about putting the washer in the freezer Would I just be better off getting a peel washer? Oh, also someone remind us which way is the correct (nonbackwards) way to put a crush washer on. |
Someone fooled with them. They should be indexed so that the 3rd (middle) slot is at 12:00. The .mil spec allows for a maximum mis-alignment of 1/2 a slot width. |
Place the complete rifle on a padded chair with the muzzle facing out on your strong side. Sit your padded ass on your rifle. Using your strong arm, apply a 3/4" wrench to the phantom. Tighten as necessary.  If you don't have a padded chair and a padded ass, then peel washers are for you. You will need a cigarette lighter or other source of flame to de-laminate the peel washer so you can peel them. I recommend needle-nose pliers to hold said peel washer before you heat up one side of it. |
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Victory is mine! I was feeling pretty bored and irritated looking at my non-indexed flash hider, so I took the bastage crush washer off and took it downstairs and threw it in the freezer... I then proceeded to watch 'Shooter,' afterwhich I took the washer and managed to get my 5c2 screwed on correctly with a combo of the shrunk washer and ar15barrels' sit/wrench technique Look ma, no dropped nut 
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