Bushmaster Problem

Discussion in 'AR-15 Discussion' started by Back40Bob, Oct 26, 2009.

  1. Back40Bob

    Back40Bob New Member

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    My bushmaster ar-15 has a major problem. the bolt will not completly seat. At one point i was able to break down the rifle and inspect the bolt asembly and noticed that there was damage to the gas piston assembly.

    My biggest issue is, i can't separate the upper from the lower because the bolt will not seat to allow the hinge to work.

    I guess i need to find a good gun smith in the eagle county colorado area that likes to work on bushys

    Suggestions?

    thanks in advance
     
  2. FCross7

    FCross7 New Member

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    Does it have a forward assist? If so, you should be able to fully seat it with that.

    -Fred
     

  3. Back40Bob

    Back40Bob New Member

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    I do have forward assist but it will not work. I really think that the gas tube is not aligning with the reciever on the bolt which is preventing the whole thing from working correctly.
     
  4. FCross7

    FCross7 New Member

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    Can you pull it back easily or is it stuck where it's at?

    -Fred
     
  5. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    If it is the gas tube to gas key alignment you can remove the gas tube. Drift out the cross pin on the gas block/front sight base. Lock the bolt open, slide the tube into the receiver and back out the front. Check to see if the bolt will lock closed. If it will you have your answer.
    Strip the upper and check the gas key. The screws should be staked into their sockets and torqued to 40 INCH/POUNDS. Look at the front edge of the key for signs of buggering upfrom a misaligned/bent gas tube. The tube should be considerably softer so it will take the abuse.
    If it still will not lock try stripping the bolt carrier group and reassembling it being careful it is done correctly. Clean the barrel extension carefully to make sure there is no debris stuck in there.
    Come to think of it, check the buffer detent (the spring loaded pin that keps the buffer/spring inside the butt stock). If it sticks up too much, it could catch on the tail of the bolt carrier.
     
  6. Back40Bob

    Back40Bob New Member

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    I can pull the bolt open. I was looking to see how to dissasemble to remove the gas tube but it was not clear to me how to do that. I am comfortable breaking down the rest of the rifle so i think once i can get the tube out, i can see if that was the problem. I'm pretty sure it is because i can see some minor damage to the gas key wher it fits over the tube.

    Thanks guys.
     
  7. crockett007

    crockett007 New Member

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    If you have recently disassembled the bolt, the firing pin retainer pin/key may have been inadvertantly installed in front of the retainer on the firing pin. It sounds to me like the firing pin is lose in the bolt carrier.

    The upper will separate from the lower, you are fighting the recoil buffer spring tension, and the fact that the cam bolt is turned fore/aft. Keep at it gingerly. If you can't get the separation, you can remove the stock (A2?,A4?) releasing the tension.

    This just happened to my friend Sunday. He has a Bushy M4. It took me about 30 minutes to finally coax the lower and upper to separate. Proper re-assembly of the firing pin solved the issue.
     
  8. Highpower

    Highpower New Member

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    Have you tried pulling BOTH take down pins (Rear AND Front)??? :confused:

    If that doesn't do it - robocop nailed it.....

    Remove the handguards, tap the gas tube roll pin out of the front sight base (1/16"). Lock the bolt to the rear and CAREFULLY grab the gas tube with a small pair of vice grips behind the front sight base (DON'T CRUSH THE TUBE!) and work it back out toward the receiver. After it's free from the front sight base, then pull it out of the upper receiver.

    If you are right about the gas key being damaged, the bolt should then fully close.

    [​IMG]
     
    Last edited: Oct 27, 2009