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Wra bolt issue

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    Wra bolt issue

    Wichita Lineman on CMP forum sent me a WRA bolt he was having trouble with going into battery.
    I cannot post pics on CMP so doing thread here and linking it to his thread there.
    What I found is checking locking lug thread lead on the lathe ,the right lug is out of position .0035" (set back )

    When I check the bolt face to left/right lug specification I find same thing. .6176" right and .5142" left.

    The left lug is actually under spec by .0008" and right is over by .0006"
    More than likely it was not running concentric when final thread grinding was done.
    So basically when bolts in battery it shifts off center due to lugs not on same lead .

    To correct this problem the right lug only needs lapped to reduce its size probably .002 . Hard to do because the bolt will want to shift off center so possible to put .001-.002 shim on left lug so bolt doesn't move off center as much .

    Ideally be nice to regrind lugs but Unfortunatly I do not have access to thread grinder or have a good enough tool post grinder to due the job correctly.

    Anyway here are the pics showing left / right lug difference .
    You can also see shiney spot in right lug corner either receiver not relieved enough on lug corner or product of bolt being shifted off center.
    Attached Files

    Oh ,and that's a huge chamfer on the outside of right lug.


      Couple more pictures of the WRA -1 bolt in question. Caliper reading measured across right lug shows the extra thickness
      about .578 . Generally they are .572 - .575. That dimension is only a rough referance though but can be used as a way to track how much is lapped off right lug if this bolt is fitted.

      And also one place to check is proper corner relief as seen on this SA right lug inside corner. This is usually very good on GI receivers but I see a shiney rub mark on this bolt where its rubbing there .
      Attached Files


        Is this something that was missed during production inspection or lack of quality control?


          Hard to say , probably in most WRA receivers this bolt would work fine. Fits perfect in one I have . But even if the bolt goes into battery its still being shifted off center just a touch .
          I've not personally seen one this bad myself ,so probably. Not that common.
          The owner was hoping to install it in a WRA receiver .