I cann't tighten my barrel nut enough

crackerbacks

crackerbacks

Sergeant
Full Member
Minuteman
Sep 17, 2010
459
36
SE Michigan
#1
I just installed a troy rail on my dpms 308. Troy states to torque it to 30-50 ft/lbs. Problem is if I tighten it past 27lbs the gas tube won't line up and it would take ALOT more than 50lbs to go the the next notch.

I tightened it to the 27ft/lbs and put a bit of blue loctite on it. Should I be concerned or just go shoot it?
 
#3
Re: I cann't tighten my barrel nut enough

And I say go to the next notch.

If the next notch is way impossible, you can grind down the notches so you can get an "in between" fit. Won't hurt a thing.
 
#4
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: himaster</div><div class="ubbcode-body">And I say go to the next notch.

If the next notch is way impossible, you can grind down the notches so you can get an "in between" fit. Won't hurt a thing. </div></div>

Yes the next notch is impossable. I took it to 60lbs and it was about half way there.
 
#6
Re: I cann't tighten my barrel nut enough

This has worked for me in the past. Apply some anti seize or some grease to the threads on the receiver to prevent them from galling. Now what you do is tighten the BN as far as it will go and then loosen it. Repeat this process several times until you get the BN lined up for the gas tube and you have achieved your desired torque spec. BTW i have built AR's for many years and never worried about torque specs on the BN. Its not an issue if you have a good fit between the barrel extension and the receiver.
 
#7
Re: I cann't tighten my barrel nut enough

If the above doesn't work. +1 for tightening it to 60lb's and then dremeling the obstructing tooth off. This method is suggested by some handguard manufacturers.
 
#8
Re: I cann't tighten my barrel nut enough

my badger said 35-60 i believe. 65 maybe. but its got a block & a nut to retain the barrel so you can put it anywhere and get it lined up. but i set the wrench at 35 ft lbs and it was 2nd try i got it lined up. i thought of backing it off and doing 40, but 35 was the start so i left it. ill look at it when i break it in.
 
#9
Re: I cann't tighten my barrel nut enough

Don't drink whiskey before your next attempt. This guy did. We all make fun of him now.




148518_10150091450696159_648051158_7318798_728454_n.jpg
 
#11
Re: I cann't tighten my barrel nut enough

Someone needs to take away his cheater bar!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">Don't drink whiskey before your next attempt. This guy did. We all make fun of him now. </div></div>
 
#13
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: himaster</div><div class="ubbcode-body">And I say go to the next notch.

If the next notch is way impossible, you can grind down the notches so you can get an "in between" fit. Won't hurt a thing. </div></div>

ROFL!!!

On and off making sure you have anti seize on there. I put a JP tube on my LR308 before heading out and the base didn't quite line up at first. Greased it up and went back and fourth until it lined up. You can also buy a tool to lap the front of the Rec just a hair and that will give you a tad more. Cutting a new notch is just asinine when with a bit more elbow grease and thought it can be done right.
 
#14
Re: I cann't tighten my barrel nut enough

toolmaker64 said:
This has worked for me in the past. Apply some anti seize or some grease to the threads on the receiver to prevent them from galling. Now what you do is tighten the BN as far as it will go and then loosen it. Repeat this process several times until you get the BN lined up for the gas tube and you have achieved your desired torque spec.



^^^ What he said
Click to expand...
 
#15
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lazy21</div><div class="ubbcode-body">you are doing ft not inch right
</div></div>

Yes ft.


I think I will try to work it a bit and see how that does. I am not real comfortable trying the dremel thing.
 
#16
Re: I cann't tighten my barrel nut enough

I agree with the recommendation to use anti-seize, grease, or something, and keep working toward the specs you want. Then, when you get really close, face off the front of the receiver so it will tighten up as much as you want. Remember that 50-65 is the MAX, and 30 is the minimum. Anywhere in between is OK, but you don't have to go MAX. I vote for facing off the receiver a few thousandths.
 
#17
Re: I cann't tighten my barrel nut enough

Anodizing on the reciever is a probobly but few thousanths thick at most. I would try using a good bench stone and just "dull" the anodizing a bit on the front of the reciever. Do not take it to the base material. A good bench stone will help you to keep it flat, and/or take off any high spots that there are. If the Barrel nut is 28TPI then one complete turn will only advance it .0357 inches. you don't need to remove much to get to the next tooth. Use the grease or antisieze too, as mentioned before.
 
#18
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Halfnutz</div><div class="ubbcode-body">Anodizing on the reciever is a probobly but few thousanths thick at most. I would try using a good bench stone and just "dull" the anodizing a bit on the front of the reciever. Do not take it to the base material. A good bench stone will help you to keep it flat, and/or take off any high spots that there are. If the Barrel nut is 28TPI then one complete turn will only advance it .0357 inches. you don't need to remove much to get to the next tooth. Use the grease or antisieze too, as mentioned before. </div></div>

Sounds like a plan... I will give it a try. This is the 5th AR style gun I have built but the first time I've had a problem to this extent.
 
#20
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Halfnutz</div><div class="ubbcode-body">Anodizing on the reciever is a probobly but few thousanths thick at most. I would try using a good bench stone and just "dull" the anodizing a bit on the front of the reciever. Do not take it to the base material. A good bench stone will help you to keep it flat, and/or take off any high spots that there are. If the Barrel nut is 28TPI then one complete turn will only advance it .0357 inches. you don't need to remove much to get to the next tooth. Use the grease or antisieze too, as mentioned before. </div></div>

Just curious how you propose keeping the receiver face perpendicular to the bolt bore (for lack of a better term)?
 
#22
Re: I cann't tighten my barrel nut enough

nw1911guy Just curious how you propose keeping the receiver face perpendicular to the bolt bore (for lack of a better term)? [/quote said:
Brownells sells such a tool for AR's to square up the receiver, although I hadn't looked for one specifically for the AR10. I'd be surprised that there isn't one.
Click to expand...
 
#23
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tbag</div><div class="ubbcode-body">

Brownells sells such a tool for AR's to square up the receiver, although I hadn't looked for one specifically for the AR10. I'd be surprised that there isn't one. </div></div>

So far, I haven't seen one for the AR10, I was just throwing that out there as food for thought. My experience is it is difficult at best, to keep things even and square when sanding or filing free hand as was suggested to the OP.
 
#24
Re: I cann't tighten my barrel nut enough

Just make sure you don't over do it and cause the barrel index pin on the extension to damage the receiver, it could really screw up your windage and cause your iron sights, if your going to use them to max out either to the extreme left or right.
 
#25
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nw1911guy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Halfnutz</div><div class="ubbcode-body">Anodizing on the reciever is a probobly but few thousanths thick at most. I would try using a good bench stone and just "dull" the anodizing a bit on the front of the reciever. Do not take it to the base material. A good bench stone will help you to keep it flat, and/or take off any high spots that there are. If the Barrel nut is 28TPI then one complete turn will only advance it .0357 inches. you don't need to remove much to get to the next tooth. Use the grease or antisieze too, as mentioned before. </div></div>

Just curious how you propose keeping the receiver face perpendicular to the bolt bore (for lack of a better term)? </div></div>

If...the barrel nut is 28tpi and the nut has 20 teeth on it he will have to remove less than .0018 of material. 28tpi=.0357" per revolution. If there are 20 teeth on the barrell nut that's .00179 per tooth. If he's sitting half way between two teeth he only needs a portion of that. Combined with a little antisieze and tightening loosening a few times he should be able to get the alilgnment he needs, while falling within the torque spec.
Placing a good flat benchstone on the face and moving it back and forth a few times should knock down any high spots (if there are any). I reccomend the benchstone instead of a file because it's less aggressive and easier to keep flat. He should be able to at least maintain the perpindicularity of what is already there, good, bad ,or indifferent.
 
#26
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Halfnutz</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: nw1911guy</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Halfnutz</div><div class="ubbcode-body">Anodizing on the reciever is a probobly but few thousanths thick at most. I would try using a good bench stone and just "dull" the anodizing a bit on the front of the reciever. Do not take it to the base material. A good bench stone will help you to keep it flat, and/or take off any high spots that there are. If the Barrel nut is 28TPI then one complete turn will only advance it .0357 inches. you don't need to remove much to get to the next tooth. Use the grease or antisieze too, as mentioned before. </div></div>


Just curious how you propose keeping the receiver face perpendicular to the bolt bore (for lack of a better term)? </div></div>

If...the barrel nut is 28tpi and the nut has 20 teeth on it he will have to remove less than .0018 of material. 28tpi=.0357" per revolution. If there are 20 teeth on the barrell nut that's .00179 per tooth. If he's sitting half way between two teeth he only needs a portion of that. Combined with a little antisieze and tightening loosening a few times he should be able to get the alilgnment he needs, while falling within the torque spec.
Placing a good flat benchstone on the face and moving it back and forth a few times should knock down any high spots (if there are any). I reccomend the benchstone instead of a file because it's less aggressive and easier to keep flat. He should be able to at least maintain the perpindicularity of what is already there, good, bad ,or indifferent.

</div></div>

I totally agree on the tightening and loosening. Just wanted to hear you elaborate further. Too many people would have the thought process (in the best bubba voice)"well the stone isn't fast enough so I should use a coarse file- dur" and I'm sure we all know where that leads.
 
#28
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Joe M</div><div class="ubbcode-body">http://www.midwayusa.com/viewProduct/default.aspx?productNumber=810457 </div></div>

I don't think they make one for the .308

Thanks to everyone who posted. I am going to attempt to file down the reciever just a hair then wark it as most recommended. It's gonna be a few days before I get time to do it, I will post how it goes.
 
#29
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crackerbacks</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Joe M</div><div class="ubbcode-body">http://www.midwayusa.com/viewProduct/default.aspx?productNumber=810457 </div></div>

I don't think they make one for the .308

Thanks to everyone who posted. I am going to attempt to file down the reciever just a hair then wark it as most recommended. It's gonna be a few days before I get time to do it, I will post how it goes. </div></div> I have built ALOT of AR's and never had to face off a receiver, Just use the tighten and loosen method it will work. If you do decide to file the receiver be carefull. If you remove too much material you can find yourself in the same situation you have now, then what are you going to do? Keep removing material until you get it right?
 
#30
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crackerbacks</div><div class="ubbcode-body"> Thanks to everyone who posted. <span style="color: #3366FF">I am going to attempt to file down the reciever just a hair</span> then wark it as most recommended. It's gonna be a few days before I get time to do it, I will post how it goes. </div></div>


<span style="font-size: 14pt">Jesus will kill a kitten if you file a 308 upper because of the bullshit you've read here!!</span>

Hand tight, then next notch. Use anti sieze and tighten/loosen a few cycles.
I thought cutting on the barrel nut was a stoopid idea, but filing on the receiver is hands down the WORST thing you could do.

I can't believe some of the stuff I read here these says. Just because AR's are modular doesn't make everybody AR experts.....

IF you have to play gunsmith remember some rules:
-you cannot cut it until its long enough
-you cannot put metal back easily
-and the biggest rule: modify the cheapest part first!!
 
#31
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Match308</div><div class="ubbcode-body">Check headspace and shoot it. </div></div>

FWIW - How tight the barrel nut is on an AR has no effect on head space. Apparently a misunderstanding on how an AR is made.

Robert
 
#33
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rcw3</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Match308</div><div class="ubbcode-body">Check headspace and shoot it. </div></div>

FWIW - How tight the barrel nut is on an AR has no effect on head space. Apparently a misunderstanding on how an AR is made.

Robert</div></div>

He knows that. Match308 meant to just get out and shoot it instead of worrying about the torque spec so much, at least thats what I took it as when I read it.

Headspace is a go >>> lock n load, enjoy.


And to add, just like everyone else said previously, apply a non-graphite moly grease or anti-seize to the receiver threads> slide the barrel in> start the barrel nut until flush> then tighten, loosen, tighten untill the next hole lines up.
 
#34
Re: I cann't tighten my barrel nut enough

When you only have one barrel nut, the problem originally posted can be a problem for sure. Options to deal with it:

1. Work the nut you have back and forth to see if you can work it in (but it seems you already tried that and that is not working out and sometimes it does not work out no matter how much fiddling you do).

2. Call up Troy and see if you can get another barrel nut or two that might provide a better fit (they may spot you a couple extra barrel nuts so you can get one that fits better and then you can send back the ones that don't fit).

3. Face off a little from the front of the receiver but we only do that with a mandrel through the receiver so the faced off face is perpendicular and true to the centerline hole through the receiver - anything else is hit or miss for being square and true.

For the hand guards we provide with our uppers we have two different barrel nuts machined, one set made up so that they bottom out half the hole spacing of the other set and that solves this issue for us. If one nut does not work, you go to the other one and you can get a decent line up within reasonable torque settings.

Robert
 
#36
Re: I cann't tighten my barrel nut enough

Grind a tooth off???? The troy I was looking at indexed off of the star on the barrel nut. Sooo, your freefloat tube with the cool interface rail will be way out of alignment.

+1 for the never seize or grease method, if that does not get it, Try a different nut.

Just a thought.
 
#37
Re: I cann't tighten my barrel nut enough

I for sure am NOT advocating a file! I'm only suggesting the bench stone after he has tried the anti-sieze and tighten loosen 3-5x method. Then only removing enough to "thin" the anodizing with a stone...and definatly NOT to the base material. I'm talking tenths (.0001) here and no more.

For those that don't grasp the term "tenth", A human hair is about 3 thousanths (.003) of an inch thick. Cut that into 30 pieces, each pc is a "tenth".

I believe SB883 knows what a "tenth" is. I also agree if you have a file in mind, you better be willing to loose a kitten.
 
#38
Re: I cann't tighten my barrel nut enough

Read a few of the posts on the remedy for this. If you don't know the answer to something don't try to answer. If you do you're not helping the OP (or group) and in fact you're making things worse. Don't want to see this website turn into another AR15.com. You'll find lots of answers over there --and about 1/2 of them wrong.
 
#39
Re: I cann't tighten my barrel nut enough

Apply white grease to the barrel side of the extension that makes contact with the nut. Put grease on the threads. Torque it down to 50 or so ft/lb back it off and repeat. Do this several times and you should be able to get it aligned. This works by rubbing through some of the parkerizing or finish (about .0015+ thick on each surface)and stretching the threads slightly. Do not get out a Dremel, file, torch, sawzall, or thermite anything. If you get it to the 60 or so ft/lbs and it's still just a hair off after you've run the nut snug several times you can just give it a little extra to get it on. If you're going for a true precision set up with as little stress as possible on everything then get the facing tool and trim the receiver down a little at a time till it torques on at about 40 or so ft/lbs.

I've literally worked on thousands of these guns and replaced a fair number of barrels and have never had to trim a receiver. Just sayin'
 
#40
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Schlafftablett</div><div class="ubbcode-body">Apply white grease to the barrel side of the extension that makes contact with the nut. Put grease on the threads. Torque it down to 50 or so ft/lb back it off and repeat. Do this several times and you should be able to get it aligned. This works by rubbing through some of the parkerizing or finish (about .0015+ thick on each surface)and stretching the threads slightly. Do not get out a Dremel, file, torch, sawzall, or thermite anything. If you get it to the 60 or so ft/lbs and it's still just a hair off after you've run the nut snug several times you can just give it a little extra to get it on. If you're going for a true precision set up with as little stress as possible on everything then get the facing tool and trim the receiver down a little at a time till it torques on at about 40 or so ft/lbs.

I've literally worked on thousands of these guns and replaced a fair number of barrels and have never had to trim a receiver. Just sayin' </div></div>

ding, ding,ding, for the win . what he said is the correct way. the if it dont fit force it method really dont work well in this instance.
 
#41
Re: I cann't tighten my barrel nut enough

Ok so I was going to try the loosen/retighten method but now is a no go. I broke my barrel nut wrench trying to break the nut loose, I guess that loctite worked a bit to well.

I'm gonna take it out and shoot it, after that I don't think it's gonna come loose.
 
#42
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: crackerbacks</div><div class="ubbcode-body">Ok so I was going to try the loosen/retighten method but now is a no go. I broke my barrel nut wrench trying to break the nut loose, I guess that loctite worked a bit to well.

I'm gonna take it out and shoot it, after that I don't think it's gonna come loose. </div></div>Why did you use LocTite? The barrel nut cant loosen as long as the gas tube is in there.
 
#45
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AXEMAN</div><div class="ubbcode-body">not only that, but wont the heat from shooting break that loctite down??</div></div>

I hope so then I can loosen it and do it the right way.
 
#46
Re: I cann't tighten my barrel nut enough

Hate to chime in late, but I did have this same problem with the Troy TRX rail, and I settled for the notch you are stuck at, my groups sucked. I ended up exchanging the rail for an MRF, and got my groups back to sub moa. You defiantly want to get to the minimum torque specs, tighter is better, unless you are experiencing a roid rage.
 
#47
Re: I cann't tighten my barrel nut enough

I had the same issue with a Troy TRX rail. As it turned out, the front of the RRA receiver was not close to square. My gunsmith made a tool that fit perfectly in the receiver and used a little lapping compound to square it up. When he was done, the anodizing was faded on one side and untouched on the the other and the thing was square.

The nut lined up, gas tube and all, and torqued to specs perfectly after that. He did use a little assembly oil.
 
#48
Re: I cann't tighten my barrel nut enough

I ordered the PRI AR15 barrel nut wrench because it appeared to be a better quality than my old do all AR tool that bent. New problem..... the hole in the PRI wrench will not fit over the chamber of my heavy .308 barrel. Anyone know of a QUAILTY AR15 wrench that will fit over such a large chamber?
 
#49
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Unknown</div><div class="ubbcode-body">I agree with the recommendation to use anti-seize, grease, or something, and keep working toward the specs you want. Then, when you get really close, face off the front of the receiver so it will tighten up as much as you want. Remember that 50-65 is the MAX, and 30 is the minimum. Anywhere in between is OK, but you don't have to go MAX. I vote for facing off the receiver a few thousandths. </div></div> thats actually the best approach,just use the big ole,flat bastard file and clear off a little then she times in perfect.no need for a dremel or torqing the hell out of it.
 
#50
Re: I cann't tighten my barrel nut enough

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: command450</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Unknown</div><div class="ubbcode-body">I agree with the recommendation to use anti-seize, grease, or something, and keep working toward the specs you want. Then, when you get really close, face off the front of the receiver so it will tighten up as much as you want. Remember that 50-65 is the MAX, and 30 is the minimum. Anywhere in between is OK, but you don't have to go MAX. I vote for facing off the receiver a few thousandths. </div></div> thats actually the best approach,just use the big ole,flat bastard file and clear off a little then she times in perfect.no need for a dremel or torqing the hell out of it. </div></div>

I want to try the grease and tighten method but I broke my barrel nut wrench trying to get the nut off, after I stupidly loctited it.
 
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