Changing upper reciever

Discussion in 'GATE AR-15 Forum' started by faceplant, Apr 30, 2010.


  1. I have a Colt H-BAR with carry handle. I will be changing out the upper reciever for a flat top keeping the 20in barrel. I have ordered an upper assembly with parts but no bcg as I will be using the colt bcg. Do I need to check the chamber or will it be adjusted already?
    Thanks
     

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  2. Constructor

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    If you keep the same bolt and barrel combination the headspace will not change so you are good to go.
     

  3. So your saying that if I get an extra BCG say from Bravo Company that I would not be able to use it in different ARs without worrying about headspace?
     
  4. Constructor

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    Most bolts are close and will not pose a problem but CMT/Stag are known to be on the large side, LMTs are known to be on the small side. If you use a Stag bolt in a LMT barrel most will be tight headspace, use a LMT bolt in a Stag/CMT barrel and there will more than likely be too much headspace. I have no idea who BCM buys their bolts and carriers from.
    Also swapping back and forth is not a good idea because the lugs of the bolt get mated to the lugs of the extension, they should be flat but nothing is perfect. I would buy a bolt for each barrel and keep them together.
     
  5. I changed out the upper reciever. The gas tube was big pain in the backside. I had to use a set of pliers to grip it and bang that with a hammer. Any tips for the next one?
     
  6. Constructor

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    installing the gas tube in the gas block, including the roll pin?
    They make a GB jig, little plastic tray but, I just lay the GB in the vise align the hole and use a roll pin starter. It looks like a long punch but has a hole in the end to hold the roll pin. Then slide the assembly over the barrel and through the hole in the receiver.
     
  7. Getting it out of the front site post while taking it apart.
     
  8. Constructor

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    If I have to pull them apart I clamp the tube in a vise and pull the f-sight base or gas block off.
     

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