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Punctured primers

Discussion in 'Handloading and Reloading' started by Herk30, Dec 20, 2012.

  1. Herk30

    Herk30 Well-Known Member

    Here's a photo of the last 5 rounds of 500 mag I shot. I happened to notice the primers were gradually struck harder around the cylinder. It's a little hard to tell but the first two or three seem to have a normal strike on them, the fourth is slightly deeper and almost punctured, the fifth is completely punctured.

    Any ideas what might cause this?

  2. rfwobbly

    rfwobbly Well-Known Member

    ► A lot of punctures with target loads are attributable to the firing pin going too deep.

    ► A lot of high pressure (or "full house") loads should be using a primer with a thicker cup.

    I don't think anyone here can help you until you tell us about your load and the brand of primer you're using.
  3. murf

    murf Well-Known Member

    need more info: weapon used, ammo description (factory or reload, bullet size and type, etc.), rounds fired since last cleaned, etc.

  4. Magnum Shooter

    Magnum Shooter Well-Known Member

    Are you using large rifle primers? Are cases made for LRP? Are you using heavy bullets?

    This form Starline.

  5. ReloaderFred

    ReloaderFred Well-Known Member

    I had a S&W Model 610 do the same thing. It turned out to be the firing pin bushing, which had to be replaced by the factory. Once they replaced the bushing, the problem went away.

    Hope this helps.

  6. fguffey

    fguffey Well-Known Member

    Picture of the primers? In my opinion there are three different say-na-eros. The first big dent is a primer that did not get crushed as in it did not have enough bang to conform to the firing pin. Pressure inside the primer forces the primer dent out and in doing so it forces the primer to conform to the protruding firing pin.

    Then there are the two in the center, normal, the primer was crushed then the pressure inside the primer forced the primer to conform to the shape of the firing pin.

    Then the last one, the one with the hole in it, that primer worked as designed but when the pressure inside the primer forced the primer to conform to the firing pin the spring (mechanical means of operation) was not strong enough to overcome the pressure inside the primer, when this happens the pressure inside the primer pushes the firing pin back. When this happens the breach face days are numbered because of the hot high pressure metal cutting gas escaping out the rear of the case cuts a big hole in the breach and or bolt face.

    The primers show definition around the perimeter of of the primer, high pressure would have flattened the edge of the primer.

    F. Guffey

    Two thoughts, one, the case/powder and bullet out runs the firing pin to the front of the chamber, or. two, the firing pin crushed the primer, then everything gets busy and in a very short (few) milliseconds including barrel time it is over.
  7. fguffey

    fguffey Well-Known Member

    Then there is the crater: A dent in the center surrounded by a high wall, something like a crater. In my opinion the hole in the last primer is without a crater. But, if you do not want hot high pressure metal gutting gas escaping from the primer rethink your methods and or techniques.

    F. Guffey
  8. Slamfire

    Slamfire Well-Known Member

    Cut your loads. If you are piercing primers the pressures are too high for your primers.

    Looked at your firing pin? Pierced primers will dish firing pins.
  9. Certaindeaf

    Certaindeaf member

    Those primers do look pretty deep down in those holes. kinda get dizzy looking at that fuzzy picture though

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