Upper reciever problems, need help!!! smh!!!!

Discussion in 'AR-15 Discussion' started by magnum05, Dec 6, 2012.

  1. magnum05

    magnum05 New Member

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    okay so i have a bush master carbine that is "carbon" and when i say carbon i mean its not the usual forged aluminum.. i bought a yhm free float and the barrel nut that came with the yhm is a tad smaller than the barrel nut that was on the ar..so with that in mind are there different sized barrel nuts or is it just because it a carbon receiver and not the aluminum??? My next question is should i just buy a new receiver or try a different barrel nut and will my barrel fit in a new different receiver?? im so pissed, i was excited to put this bushy together and now im at a dead end with this damn barrel nut b.s.

    You guys help me a lot so far i could only think to come here and hope for the best resolution!! Any good receivers around $100??? i have a few in mind like yhm, del-ton, rra but just figured id ask
     
    Last edited: Dec 6, 2012
  2. willfully armed

    willfully armed New Member

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    Barrel nut threads should be all the same on the ar15 platform, unless Bushmaster pulled a proprietary FU, do you have a dial caliper? Measure inside radius of the nuts.

    Be sure to lubricate the threads with good oil AFTER cleaning them WELL.

    Torquing to 30#, back of slightly, then to the next keyhole not exceeding 80#.
     

  3. c3shooter

    c3shooter Administrator Staff Member

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    You have a CARbon 15- and the design is a smidge different from the standard AR. Parts may not fit.
     
  4. Jpyle

    Jpyle New Member

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    When you say that the barrel nut is smaller do you mean that it does not allow the barrel to be secured to the receiver or that the outside diameter of the barrel nut is smaller than the one supplied. Reason I ask is that the free float tube mounts to the supplied YHM barrel nut and the diameter may be different. The 2 barrel nuts are not interchangeable so there is no need for them to be of similar size.
     
  5. dickpalmer

    dickpalmer New Member

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    Call Bushmaster tomorrow. They will have some info for you. If the barrel nut won't thread on, you can't use it obviously. They may have a recommendation for you.
     
  6. magnum05

    magnum05 New Member

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    The barrel nut that came with yhm free float is a smaller diameter than the barrel nut/delta ring that was on the ar to secure to barrel to the receiver..
     
  7. Gatoragn

    Gatoragn Active Member

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    Palmetto State Armory has stripped uppers on tonight for $54.99. Regular price is 99.99 + shipping. This is a great stripped upper.
     
  8. magnum05

    magnum05 New Member

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    Yeah I seen that but they don't have m4 feed ramps and my barrel has them so wasn't sure if I could use that
     
  9. Gatoragn

    Gatoragn Active Member

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    Good catch.
     
  10. magnum05

    magnum05 New Member

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    I measured both barrel nuts and it's a .050 difference, so im going to stick the yhm barrel nut which is a smalller I.d than the original nut in a lathe and take down the i.d of the threads .025 and see what happens..thanks for the help guys
     
  11. magnum05

    magnum05 New Member

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    Modification went perfect! Re-machined yhm barrel nut to same specs as bush master barrel nut and rethreaded the yhm nut and fits like Oj's glove...nice and tight