Checking headspace

Discussion in 'AR-15 Discussion' started by capnklump, Dec 30, 2013.

  1. capnklump

    capnklump New Member

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    When doing a build, if you start out with quality parts, is it absolutely neccessary to check headspace? Cause if I had to do that I'd probably rather let a gunsmith do it just to know its safe to fire.
     
  2. KG7IL

    KG7IL Active Member

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    My opinion(s)

    1) Yes, checking headspace is important and must be done.

    2) No, if you got parts and have to build a freedom rifle for immediate use, then you are good to go. What do you have to loose.

    Most likely you are going to be fine, but how will you know unless you check.

    If this is your only build, then do drop by a LGS that has an in-house shop.
    I'm sure that they would do this for quite quickly. Buy something from them if they don't charge you.

    You may find that the LGS has a set of guages for sale around $30. Just the think if you plan on more builds.

    Please note: #1 is the correct answer. #2 is really quite silly now, isn't it.
     

  3. capnklump

    capnklump New Member

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    The gauges you're talking about are the "go gauge" & the "no go gauge"??
     
  4. SSGN_Doc

    SSGN_Doc Well-Known Member

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    On an AR a field gauge is enough. If the headspace is off the whole barrel assembly or the bolt is trash, because you cannot adjust it. The bolts are all supposed to be made to the same dimensions. So, you could hope you got a bad bolt.

    If a new bolt won't headspace, then the barrel is trash. The barrel extension has to be headspaced at the time the barrel assembly is put together. Once it the barrel extension is set at the proper headspace the extension is drilled and pinned with the indexing pin that lines the barrel up in the upper receiver. Then the gas port is drilled to be at top dead center based on the index pin. If you had to adjust the barrel extension after the fact, your index pin or gas port or both would not be lined up properly to allow sights to line up, or the gas block and gas tube to align.

    So, generally a new barrel and new bolt are going to headspace, but this should still be verified.
     
    Last edited: Dec 31, 2013
  5. KG7IL

    KG7IL Active Member

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  6. JonM

    JonM Moderator

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    When you check headspace you have to remove the ejector for a true test. Leaving the ejector in can cause the gauge to bind and give a false bad reading.

    Ar15 barrels are pretty strong. Signs of excess headspace are greatly lengthened cases or split shoulders. They will kaboom if its too far out of spec and its why I never buy bargain barrels bolts or uppers and always buy from sources that properly test like rra colt bcm.
     
    Last edited: Dec 31, 2013
  7. gunny91

    gunny91 New Member

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    Headspace is important especially if ur want an accurate trustworthy firearm

    Sent from my XT901 using Firearms Talk mobile app