Scratch on shoulder

Discussion in 'Gunsmithing' started by padd54, Sep 25, 2009.

  1. padd54

    padd54 Well-Known Member

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    I just shot a "new to me" rifle, 3 factory and 6 virgin case handloads.
    When I got home and inspected the brass, each has what looks to be a scratch about half as long as the shoulder, in the same place on each case.
    Also, there are scratches on the outside of the extractor land.

    Do I have major problems? The scratches are very evident.

    Thanks,
     
  2. J E Custom

    J E Custom Well-Known Member

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    Try single loading (Lay one round in the action and push it in as far in the chamber as you
    can with your thumb and close the bolt on it).

    This will tell you if you have a sharp edge that is scratching the brass during the magazine
    feeding process .

    This is most likely the problem and can be fixed .

    The staggered feeds are notorous about this .I have switched almost all of my rifles to a
    center feed mag box to stop marking up my brass and the bullets.

    J E CUSTOM
     

  3. padd54

    padd54 Well-Known Member

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    OK, I single fed by hand a round several times, no scratch on shoulder.
    I then fed several rounds with the magazine, which is single stack, and the scratch is not there. However, there is a small mark about 1/10 the size of the original scratch.

    What about the marks on the extractor land?

    Thanks for your help,
    Ray
     
  4. Gene

    Gene Well-Known Member

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    Pics would help. Not sure what the extractor "land" is. Do you mean extractor groove?

    If this is not a magnum, headspace is taken on the shoulder at datum line. So I would be concerned about a scratch on the shoulder, possibly indicating a burr in that area. If this is the case, a gunsmith can polish it out. Very light scratches may not be significant, and may not affect safety or accuracy, but I would want them out.
     
  5. padd54

    padd54 Well-Known Member

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    This is the best picture I could get with my old camera. There is no metal build-up at the edges, it as if it was cut.

    The other scratches that was referring to, are on each side of the extractor groove. 338LM.

    Thanks for all help,
    Ray

    [​IMG]
     
  6. Gene

    Gene Well-Known Member

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    The scratch does not appear to be deep. It is longer than it is wide. I doubt it is of any consequence. If this is a brand new gun, return it to the manufacturer (call them first); if its a used gun, a smith can easily polish the shoulder area of the chamber and remove it.

    What make rifle is this? Push feed or controlled feed?

    I can only guess that similar scratches near the extractor groove could be a weak ejector spring, or case touching the port wall.
     
  7. padd54

    padd54 Well-Known Member

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    It is an used AR-30 that shot right at .5moa for the rounds that I fired from 112yrds.
    I am unsure of what you mean by "type" of feed.
    I will find a Smith to take a look at it.

    Thanks again,
    Ray