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non circular dents in spent primer

Discussion in 'Handguns: Autoloaders' started by XxR3M0V3RxX, Nov 14, 2012.

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  1. XxR3M0V3RxX

    XxR3M0V3RxX Member

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    I have a ruger Sr9c. I recently noticed that the spent casings are exhibiting a non circular dent in the primer area. It looks like the regular dent plus a line travelling from the center of the strike to about two thirds across the primer face. I don't know if this is normal for auto pistols or if I have a developing problem. I have no other issues with the gun and it gets cleaned regularly. Please advise, thanks in advance.
     
  2. silicosys4

    silicosys4 Member

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    I have no answer, but I will say you aren't alone, I have several pistols that do this...leaving a drag mark with the dent. The dent also is in inconsistent areas of the primer, sometimes dead center, sometimes almost to the edge of the primer. All the pistols I have that do this seem to be striker fired as well.
     
  3. brickeyee

    brickeyee Member

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    You need to post a good macro type close up photo of the primer and the firing pin tip.
     
  4. Wil Terry

    Wil Terry Member

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    THAT IS FIRING PIN DRAG, and it has only been around some autoloading pistols for some 90 years now. A heavier firing pin spring usually cures it.
    And so it goes...
     
  5. tightgroup tiger

    tightgroup tiger Member

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    I agree, I have an SR9 and it does the same thing. Nothing to worry about.

    The firing pin is still extended while the slide starts back and as the case tips up to be ejected the firing pin drags across the primer face.

    Nothing wrong with your gun. When I buy range brass, most all of the 9mms look like that.
     
  6. PO2Hammer

    PO2Hammer Member

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    AKA firing pin wipe.
     
  7. Coltdriver

    Coltdriver Member

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    Also known as firing pin wipe. Glocks are notorious for this.
     
  8. XxR3M0V3RxX

    XxR3M0V3RxX Member

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    Thanks guys. I feel much better about it now.
     
  9. chris in va

    chris in va Member

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    Basically the case is being ejected while the pin is still making contact with the primer.
     
  10. wally

    wally Member

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    Not to mention the rectangular imprint Glocks make :)


    As long as the gun is not having stove pipe ejection failures its nothing to worry about.

    Some reloaders consider it to be a sign of overpressure, and it can be as long as you can be sure that the pistol doesn't do it on factory loads.
     
  11. jojo200517

    jojo200517 Member

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    Have yet to see a glock that didn't do this, my taurus also does it, seen plenty of other brass out of various pistols that look about the same. Seems to be something that happens moreso in striker fired pistols from what I have seen.

    Also primer flow from overpressure will usually look different.
     
  12. Skylerbone

    Skylerbone Member

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    Have a look at your breechfaces fellas. The odd imprint will show up there as well; as a small crater next to firing pin hole. Put there to give debris a place to go while allowing the pistol to continue to function. Conspiracy theorists will claim it's a micro-marking cut out to positively ID brass.
     
  13. ku4hx

    ku4hx Member

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    That's why after picking up all my brass I throw down a [gloved] handful of decoy Aluminum and Berdan primed cases to misdirect those who are after me.
     
  14. Skylerbone

    Skylerbone Member

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    I like your style and your thinking! Nothing says "huh..." like a staged scene;-).
     
  15. mljdeckard

    mljdeckard Member

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    Interesting, I never knew this.
     
  16. highorder

    highorder Member

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    My M&P9 wipes primers too. Doesn't appear to vary with ammunition, and doesn't affect function. I ignore it.
     
  17. hentown

    hentown Member

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    I've fired over 300,000 rounds of my reloads through my various Glocks. I've NEVER seen a case of firing pin drag on any of the fired cases. Glocks do exhibit a rectangular firing pin strike on fired brass, but that's irrelevant to this discussion.
     
  18. Coltdriver

    Coltdriver Member

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    Well hentown I guess we are in the presence of the final word.

    I have seen different on my Glocks. Does not make your experience of inspecting 300 thousand cases invalid though.
     
  19. Quoheleth

    Quoheleth Member

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    In my experience, I noticed this in my striker-fired guns - SR9c, M&P, Taurus 24/7, and Kahr CW9. My CZ85 and Taurus PT92 did not do this.

    Q
     
  20. SDC

    SDC Member

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    In the Glock, the firing-pin wipe is contained entirely WITHIN the extruded area of the primer, so, it'll be there, but probably not very visible without a microscope. This characteristic is seen in all pistols that use the Browning-style (link or cam) method of locking the breech; as the rear of the barrel drops to unlock, the primer is still pressed tightly against the breech-face, and that's what leaves these marks.
     
  21. hentown

    hentown Member

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    I'm certainly no "final word," but I can attest that none of my Glocks ever exhibited any primer wipe. If one has to examine a case with a microscope, in order to see the so-called primer wipe, then that's not the same anomaly described by the OP. ;)

    I do suppose that my limited experience with Glocks would tend to invalidate the statement that "Glocks are notorious for that," though. ;) FWIW, a Glock's firing pin spring works exactly reverse of how a 1911's firing pin spring works, and that information is germane to this discussion. :eek:
     
  22. SDC

    SDC Member

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    Here's an example of a typical Glock "primer wipe"; in this case, the firing-pin drag is the triangular area outlined in red, and this is caused by the nose of the firing-pin remaining stuck forward out of the breech-face while the pistol unlocks (the barrel drops, while the firing-pin stays where it is), and you should see this to a greater or lesser extent in ANY Glock, because that design has no method for retracting the firing-pin until after the slide has reached its most rearward travel.
     

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  23. Jim K

    Jim K Member

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    It hasn't been around since auto pistols were invented, but it has been around since Browning invented the dropping barrel system. There are several possible causes, none of any consequence as long as what is causing it doesn't interfere with functioning.

    Jim
     
  24. W.E.G.

    W.E.G. Member

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    Smith and Wesson Model 59

    [​IMG]
     
  25. ritepath

    ritepath Member

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    My PT145 always does this. Looks like you dotted an i
     
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