You were crushing the crush washer. You should have crushed it down where bottom was at 4 or 5 o’clock then loosened flash hider the retighten where bottom is at 6 o’clock with proper torque.
You might be able to loosen and retighten correctly but my guess is you collapsed the crush washer too much already to get proper torque with it being aligned correctly.
Too much torque can affect accuracy on a muzzle device.
There is no torque spec for crush washers. They crush at about 25 foot pounds or so, and that stays pretty much the same until they bottom out. If it suddenly gets much harder, then you’ve likely bottomed out. As far as backing off after each quarter turn, it depends on the situation. If it has to travel very far, say over 300 degrees, then doing a little pre-crushing seems to be preferred. But it shouldn’t be necessary. If you started out at 1, then you should not have exceeded 360 degrees, which is well within normal. I think a mil spec crush washer has 450 degrees of rotation before it bottoms out, so you should not have been meeting that kind of resistance if I understand your situation correctly. If you’re really at 80 foot pounds, which it sounds like you probably are, then something is very wrong. Installing a muzzle device on a crush washer should never involve a breaker bar, ever. It should be easy enough that a child could do it with a plain old wrench.
Depends on the crush washer. DPMS uses some that are soft like Philly cream cheese. I have also noticed that with melonite/QPQ barrels it seems a little harder.
I have noticed some differences in crush washers between brands and batches, but that can’t be what’s going on here. We’re talking like 5 or 10 foot pounds difference between different brands.
The minute the breaker bar comes out for a crush washer it’s a definite FUBAR and then some, especially when you’re “putting all you have” into it. The amount of force a grown man can generate with a breaker bar is pretty insane. I just hope he’s a short dude and it was a small breaker bar, or he may have far exceeded 80 foot pounds.
My advice would be to start over with a new crush washer, preferably a different brand if possible, and watch some videos on the installation. There must be hundreds of youtube videos on that subject.
Thanks for the replies. I’m no monster sized guy…but I aint weak either. Blue collar guy my whole life…work on my own vehicles…carpenter for 15 years…
I tried the method of backing off and tightening…and that seemed to work to get the bottom to 6 oclock…but
It was like I was trying to tighten a lug nut on a tire…or better yet breaking a very tight lug nut loose.
Believe me when I say I’ve watched a ton of video on installation…thats what is baffling me about the whole thing…still don’t understand what in the world was going on. My guesstimate on the amount of force is just that. It was HARD to turn. I did grease the threads whith Aeroshell 33 beforehand.
I knew I had no choice to get it to time correctly…
Are you absolutely positive that the crush washer was new? It sounds to me like it’s bottoming out. My only thought is that maybe someone sold you a used crush washer or it was just a bad batch. Sorry I can’t help you more. My only advice would be to switch to a different brand of crush washer and see what happens. But if you find yourself in the same situation again, needing a breaker bar that is, don’t force it. That kind of force will definitely cause problems, perhaps permanently.
Did you chase the threads in the old FH? You may have run into carbon that built up beyond the muzzle on the old barrel. A test fit without the washer would have told you that.
Nope…never knew that might be an issue…until right now…geez… i do seem to recall doing just that and it would not thread all the way on… So I’m an idiot who thinks he knows what he’s doing…great. i can’t stand doing things incorrectly… OCD.
I went to a local guy (so I could have someone there to help me if I needed it) who allowed me to go at it on my own the first time I swapped the barrel. It was then I realized I couldn’t continue because my existing gb was a taper pin. So I of course stopped, went home, and ordered a Faxon gb. On my way out I asked if he had another crush washer and he gave me one… I’m assuming it was new. This was about a week ago. I put it all togehter last night at the shop where I work. All went well except for this FH.
I’d have to pull the rail back off to pull the fh.
Don’t beat yourself too bad. None of us were born knowing everything. If you decide to take it off and it’s a standard DD A2 FH I wouldn’t bother to clean it. Even a cheap 1/2 28 bottom tap will cost 3 times what a $9 A2 does.
Well I guess thats the next question…do I need to remove it, clean it up, and reset it? Is it to much force on the end of the barrel? Or, is any damage already done and I screwed myself?
You probably didn’t hurt anything and if you did taking off isn’t going to fix it. If you really did pull it to 80 f/p whatever you do don’t try to remove it with a reaction rod.
First of all, I doubt you did any permanent damage, so just slow down and take it easy. All the threads are steel, and you used assembly grease, so you’ve got that going for you. It’s also a relief to hear that the breaker bar was only 14’'. Knowing that, I’d say your estimate of 50-80 ft/lbs is probably close. It’s way too much torque, but not enough to cause permanent damage in and of itself.
But you do need to remove it and do it right. With it on there that tight, you won’t have decent accuracy, and if you shoot it like that very much then the muzzle will wear unevenly with the rest of the barrel and make the problem permanent. When you overtorque the muzzle device, it squeezes the muzzle closed a few thousandths, making a constriction.
As for the carbon build up, I don’t think that’s your problem. The carbon can make it difficult to thread on by hand, but carbon is soft and steel threads are sharp. In my experience, you wouldn’t even notice it, especially with that breaker bar on there. Assuming the threads weren’t damaged to begin with, I think the crush washer is most likely the problem. The guy could have gotten them mixed up and given you an old one, or some people do use them multiple times. Most often you can get two uses out of them without any problems, so people like to push it. For a buck fifty, though, it’s just not worth it.
Well she’s unfired so it looks like I’m due for more practical experience.
Can you recommend a good barrel vise setup? Lotta options out there. Reaction rod would be great, but I’m married… no way 100 bucks for a possible one time use will fly.