Flattened Primers?

Discussion in 'Reloading' started by Dannyd, Mar 26, 2010.

  1. Dannyd

    Dannyd Active Member

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    Jan 18, 2010
    Hi Folks,
    I'm really not certain what a flattend primer (that i should be worried about) looks like.
    After i shoot any bullet from min to max out of my 7mmRM, the primer never looks exactly like a brand new primer. It is always flatter.

    I do not see any cratering from the firing pin but the primers are certainly flatter.

    How do i know if i have a problem?
     
  2. Gunpoor

    Gunpoor Well-Known Member

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    Apr 28, 2007
    Reading primers isn't totally reliable for determining chamber pressure but it certainly is a decent indicator. In my limited experience when the entire visible surface of the primer is flattened and the edge of the primer is almost indistinguishable you are in very excessive pressure. Usually when the primers are showing this deformation the case heads are also showing shiney spots, and often bolt lift is stiff when extracting the empty case.
     

  3. 3006savage

    3006savage Well-Known Member

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    Jul 16, 2008
    I am interested in seeing the responses to this topic. I question how good of an indicator they really are. I shoot an 06 and have had several factory loads with completely flattened primers.(Hornady and Winchester) Keep in mind that factory 06 ammo is designed to operate below 60,000 psi. Considering the same primers are used in a 270 which operates at 65,000 psi I have my doubts about flattened primers as a "tell all" pressure sign.
     
  4. mkg

    mkg Well-Known Member

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  5. outofayr

    outofayr Well-Known Member

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    Nov 20, 2008
    For me, the Win primers were softer than CCIs BR primers...load that flattened WLR primers didn't flatten the BR2s...

    Brian