Why Dented 10mm Brass?

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  • Converted Glock 21 with:
    6" Alpha Wolf 10mm barrel
    20lb spring (factory .45 is 17lb)
    Factory G20 mags
    Factory G21 extractor
    Handload- 165gr HST, 14.0gr AA9, CCI 350 (magnum). This is below max published load data and the only load signs are slightly flattened primers.

    Bottom left brass- why are they dented? Everything was damn close to identical in all the loads (single stage/hand weighed)

    ETA- Case ejection is very random as well. Some go 3-4 o'clock, some go straight up and some come back at my face. I am confident the charges are all within .2gr and OAL is very tight.
     

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    GuitarmanNick

    Ultimate Member
    Jan 9, 2017
    2,221
    Laurel
    Kind of tough to really see from the angle of the picture.

    Is the brass all the same, or mixed headstamp? Perhaps the case walls are just a little thinner than the others making them more susceptible to neck damage. I think I am seeing some small dings on other cases in the picture but those look a little thicker to me. They 4 really bad ones also appear to be slightly longer than the others in your tray.

    I usually trim all of my brass before reloading the first time. This insures they are all the same once the bullets are seated and crimped. I would think having different length cases could be why the ejection pattern is not consistent, too. I have not been reloading as long as most, but that is my .02 cents.
     
    Last edited:
    Kind of tough to really see from the angle of the picture.

    Is the brass all the same, or mixed headstamp? Perhaps the case walls are just a little thinner than the others making them more susceptible to neck damage. I think I am seeing some small dings on other cases in the picture but those look a little thicker to me. They 4 really bad ones also appear to be slightly longer than the others in your tray.

    I usually trim all of my brass before reloading the first time. This insures they are all the same once the bullets are seated and crimped. I would think having different length cases could be why the ejection pattern is not consistent, too. I have not been reloading as long as most, but that is my .02 cents.

    All brass is virgin Starline brass from the same shipment.
     

    Bountied

    Ultimate Member
    Apr 6, 2012
    6,884
    Pasadena
    Try getting a 10mm extractor and ejector for your G21 slide. I had a similar issue with a lone wolf conversion. .40 to 9mm, sometimes the brass would fly back and hit me in the face. I put in a 9mm extractor and ejector and ejection was much more consistent.
     
    Last edited:

    alucard0822

    For great Justice
    Oct 29, 2007
    17,643
    PA
    Looks like it's dropping off the extractor, or not getting tossed by the ejector, and getting caught in the slide on the way forward, as bountied said, 10mm extractor and ejector should help, big difference in rim diameter.
     

    PowPow

    Where's the beef?
    Nov 22, 2012
    4,712
    Howard County
    There are a couple good threads about this on the glocktalk forum. This one seems relevant. I was curious to see what they were recommending as some day I might want to try this with my 21.
     

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