Winchester Primers-Blowby
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  1. #1
    Senior Member
    Join Date
    Oct 2013

    Default Winchester Primers-Blowby

    People on other boards are reporting gas smudges on the base of their reloaded cases. They are attributing it to Winchester primers. I called Winchester and the guy I talked to said they were unaware of any problem with their primers. He suggested that anybody having this problem should send the spent primers to Winchester for analysis. He gave me a number to call for instructions on sending them: 618-258-3453

  2. #2
    Senior Member NGF Addict!
    Join Date
    Feb 2013


    News to me.

  3. #3
    Junior Member
    Join Date
    Dec 2013


    And how many times have the cases been reloaded??

  4. #4
    Senior Member NGF Addict!
    Join Date
    Jul 2012


    It's likely that there is nothing wrong with the primers, but some brands of cases are not a good match for some brands of primers. There is a variation in the size of primer pockets as well. If a primer is too easy to seat, it doesn't fit snugly & there will be some gas blow by. Hot loads could also cause it.

  5. #5
    Join Date
    Dec 2013


    Sounds like loose primer pockets to me. Cases should be tossed.

  6. #6
    Dr. of Loadology Gunrnr's Avatar
    Join Date
    Jul 2007
    Upwind of Albuquerque, New Mexico, USA


    Win pistol primers are very slightly smaller in diameter than CCI. I have used this fact to my advantage for many yrs by using them for several foreign cases (in .45 ACP) such as S&B, Magtech and Privi, that have smaller primer pockets.

    I know...I know...spec says they're all the same. But they're not. A micrometer belonging to a friend, that is much more accurate than my own, shows appx 0.00001 to 0.000015 delta between Winchester and CCI, with Winchester being smaller.

    We did not find this difference in rifle primers. I cannot explain any of these facts but I can confirm them with my own experience. It has saved me throwing many, MANY perfectly good cases into the scrap pile.

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