AR barrel nut stuck

Discussion in 'Firearms' started by Lancer, Mar 16, 2018.


  1. Lancer

    Lancer TANSTAFL! Site Supporter+++

    OK, so my bro'n'law brings me an upper. Everything is off and he wants me to install a free float he got at a show. No problem.....
    That barrel nut is on something north of 200 ft lb. That's what I weigh, and I was doing pushups on an 18" breaker bar plugged into the nut wrench try to free it.
    Any ideas before I cut off the D-ring and take a thee foot pipe wrench to it, along with some serious heat? I'm thinking it was put on with red locktight or similar.
     
  2. Tully Mars

    Tully Mars Metal weldin' monkey

    I'm surprised the wrench didn't round off some of the points on the nut. If you have a really small tip for your torch you might get it hot enough to break loose with out damaging the delta ring or spring but I doubt it. You are most likely going to trash the ring and spring. I've never had one that hard to break loose, not even close. Be careful using heat as it doesn't take much to ruin the upper, even deflected flame/heat can get the upper too hot if used too long. Wet some cloth towels and wrap the upper real well before applying your heat. Are you using a barrel vice or a receiver block?
     
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  3. 3M-TA3

    3M-TA3 Cold Wet Monkey

    Aluminum expands more than steel (13.1 vs <9) when applying heat, so I would freeze it instead of using heat.

    Thermal Expansion of Metals
     
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  4. oil pan 4

    oil pan 4 Monkey+++

    A torch should cause the lock tight to fail before the aluminum heat treatment is altered.
    Be sure to use heat sinks.
     
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  5. Lancer

    Lancer TANSTAFL! Site Supporter+++

    >> T M - a receiver block
    >> 3M-TA3 - hmmm might get loc-tite brittle enough to shear if that's the problem. Grocery stores have dry ice around here..
     
  6. v0lcom13sn0w

    v0lcom13sn0w Trunk Monkey

    righty tighty lefty loosie :ROFLMAO::ROFLMAO:



    its easy to crack an upper if youre using a clamshell vise block vs a reaction rod or BEV block so just be careful!!
     
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  7. Lancer

    Lancer TANSTAFL! Site Supporter+++

    Normally I can use one of those multi-tool wrenches. I put that aside quite quickly on this one, and got out the armorers wrench. That's why I;m thinking red loc-tite or similar. That stuff takes 350 F to break.
     
  8. ghrit

    ghrit Bad company Administrator Founding Member

    Try this before heating and cutting. Use the wrench, put heavy pressure on it and simultaneously tap-tap smartly on an exposed part of the nut. Or just accept the inevitable and break out the angle grinder (or Dremel and a LOT of abrasive disks.)
     
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  9. 3M-TA3

    3M-TA3 Cold Wet Monkey

  10. RouteClearance

    RouteClearance Monkey+++

    If the barrel nut was installed with Loc-Tite then instead of using direct flame, heat your oven to 375 degrees. Put the upper in the oven for about 20 minutes. Use some oven mitts to put the upper in your receiver block, then try and break the bond before everything cools down.
     
  11. ghrit

    ghrit Bad company Administrator Founding Member

    Dunno how it goes at your place, but my uppers will not fit in my oven. (Do a cold oven check for fit, first.)
     
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  12. Brokor

    Brokor Live Free or Cry Moderator Site Supporter+++ Founding Member

    Nobody should ever use LocTiTe on that location. I would spray and soak in your favorite break free oil overnight.
     
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  13. ghrit

    ghrit Bad company Administrator Founding Member

    Agree. If there is loctite in there, that makes me think this is not a new upper. Bro in law might know more than he told.
     
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  14. Ura-Ki

    Ura-Ki Grampa Monkey

    Never had one that friggin tight! I also suspect lock tite! Also agree with the oven trick as long as it fits! Wrap your receiver in tin foil and a wet rag firstly, then heat! Don't wanna loose the heat treat on that receiver! You could also use dri ice on the barrel and a heat gun on the receiver! Careful you don't smoke your fingers!
     
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  15. ochit

    ochit Monkey+

    Use it for a tomato stake and tell your Bro in law he's a meat ball trying to pass off a problem to you.

    I have that now and again people bring in a box of parts or the part they can't figure out or disassemble, reassemble.

    Squirt a bit of penetrating oil let it set in the sun or use a heat lamp, then vice up with a good block and wrap with leather use your wrench, you need another person to apply pressure and you use a 2X4 against the nut and use a air chisel on the board to set up a vibration and NOT allow the chisel to touch the parts only the board and the chisel across the woods grain or else it will split. Vibration or harmonics and constant pressure can work. there is also heat control paste if you decide to heat it, any welding shop should have it.
     
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  16. duane

    duane Monkey+++

    Should have to be 65 and have your mothers written permission slip to buy red lock tite. Blue is ok, but it takes heat or shock, think impact wench type shock to break red lock tite loose. Often run into it when trying to replace chucks on drills. Often easiest way to do it is the grinder route and just bite the bullet. I have used a lead hammer to hit the wrench with some success. I put pressure on the wrench and hit the wrench as close to the nut as I can with the hammer to negate as much as possible the spring in the wrench handle. I have used a paste that Brownells at least used to sell when doing bolt work many years ago and it an damp rags worked then to protect the heat treat. Have had no luck with propane torch, flame is to wide and not hot enough, time to get a really fine tip on a torch and two people, heat it hot quick, put pressure on it while heating or as quick as possible afterwards, and cool quickly once it comes loose. There is a reason that they tell you to use the grease when you torque a barrel up and in my limited experience I have never heard of one coming loose. Now manifold studs on 70 year old tractors, or located behind the cross member as on a v-8 pickup are a whole different story. In my lifetime, the two greatest destroyer of firearms have been do it your self gun smiths and rust. In the long run it looks like it is going to be democrats.
     
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  17. Lancer

    Lancer TANSTAFL! Site Supporter+++

    I get "the boxes" occasionally as well. My favorite is a Ruger Mk series .22 pistol. The so-called gunsmiths can't put them together. I have four of them now: one I actually purchased, the others given to me by terminally frustrated owners...
    Although... One of my co-workers handed me a disassembled distrib out of a '63 SAAB once. He had absolutely zero concept of points & rotor....
     
    Last edited: Mar 17, 2018
  18. Lancer

    Lancer TANSTAFL! Site Supporter+++

    It's definitely not new. He didn't say where he got it, but it's dirty as hell, bolt carrier was stuck to the handle, couldn't even see the pin retainer, feed ramps are pretty well used as well. Barrel looks like it was chromed, but I had to scrub it a bit with a bore brush to tell. If I were to guess, I'd say a ton cheap steel cased Russian surplus, and never, ever, cleaned.
    Receiver is proof stamped with "PSA", so I assume and older build from Palmetto State in SC. Maybe I should drive down and let them deal with it.... And a shopping trip is alway a good justification :)
     
  19. RouteClearance

    RouteClearance Monkey+++

    Would it be easier to just buy a new upper and barrel? If this has had a lot of round shot through it, then it would also be wise to replace the bolt/bolt carrier. Not to knock PSA, but I would only use them if I was on a tight budget.
     
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  20. I agree with the idea of thermal shock. Cool the assembled upper, (dry ice?) apply heat to the nut (small map torch?). Shrink the male threaded portion (barrel shank will act as a heat sink), enlarge the female threaded part. Then how do you clean the thread lock out of the threads? I once had to clean the internal threads on a Mazak lathe where assemblers had used thread lock to install a prox switch. Couldn't find a tap with that dia and pitch. Took most of an eight hour shift. But I got it working. And there is also a green lock-tite. that Is PERMANENT!!!
     
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