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Thread: Primer bulged

  1. #1
    davederrick's Avatar
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    Primer bulged

    When I was decapping a lot of .357 cases, I noticed a few (2 out of 100) primers were bulging in a convex shape, even the firing pin dent seems to have been pressed out evenly, so I doubt the decapping did it. The other cases (98 out of 100) looked normal, big dent for the firing pin & the primer face slightly concave.

    Is this an overpressure indicator ? There were no other obvious signs. The load was 5.5gr of Red Dot with a 158grFP bullet, I know this is pretty much the "never exceed" load. I have used this load before & never noticed any problems, the recoil didn't feel excessive in my Taurus LBR when compared to shooting factory magnum loads.

    Should I just ignore it, or step the load down a touch ?

    Thanks in advance.
    "I'm all in favour of keeping dangerous weapons out of the hands of fools. Lets start with typewriters." - Frank Lloyd Wright (1867-1959)

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    hi

    Dont know about pistol cartridges but that is a sign of something not being right....pressure signs on neck are of great concern but coming back towards YOU are a big No-NO. Are there any other signs?

    Are you weighing each load or throwing them ? are you loading to SAMMI specs.

    Someone with more experience should be able to steer you right but my tenpeneth is FIND out more before you reload

    PLUS - i would get some pictures hosted and link them on here....may be easier for someone to identify by looking at the image

    Are you using a different bullet ?

    Above all - BE SAFE

    ATVB,

    Gary
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    Did you notice the bulging before you decapped them - or are you looking at decapped primers ...

    Roy
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    davederrick's Avatar
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    Heres 2 primers -
    http://www.davederrick.aquiss.com/images/Primers.jpg
    I thought the one on the left was OK, but now its magnified it does look like cratering around the firing pin. The one on the right is one of the ones I thought looked blown out. Think I'll step the load down a bit.
    "I'm all in favour of keeping dangerous weapons out of the hands of fools. Lets start with typewriters." - Frank Lloyd Wright (1867-1959)

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    Quote Originally Posted by davederrick View Post
    Heres 2 primers -
    http://www.davederrick.aquiss.com/images/Primers.jpg
    I thought the one on the left was OK, but now its magnified it does look like cratering around the firing pin. The one on the right is one of the ones I thought looked blown out. Think I'll step the load down a bit.
    But did you notice the bulging before you decapped them ?

    .

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    It definitely seems as though some of your reloads are a bit on the high side.

    You are wise to step the load down a little bit until you know the cause.

    Something simple like a slightly oversize bullet or a tight crimp can cause the pressures to go up. Mixing cases can have the same effect because the internal volumes vary due to the thickness of the brass.

  7. #7
    davederrick's Avatar
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    Quote Originally Posted by harricook View Post
    But did you notice the bulging before you decapped them ?

    .
    No, but I wasn't looking - only after I decapped them. After I spotted it, I did look at the remaining rounds before decapping & didn't see any more that looked wrong.

    Quote Originally Posted by enfield2band View Post
    Something simple like a slightly oversize bullet or a tight crimp can cause the pressures to go up. Mixing cases can have the same effect because the internal volumes vary due to the thickness of the brass.
    All the same cases, perhaps I'll go for a lighter crimp as well as stepping the load down.

    Cheers guys.
    "I'm all in favour of keeping dangerous weapons out of the hands of fools. Lets start with typewriters." - Frank Lloyd Wright (1867-1959)

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    I personally think that decapping caused the bulge

    Carry on loading as you are now & check the next batch of empty cases prior to decapping (or when you are shooting) ..

    I shoot 357 Mag using Accurate No 5 in a Marlin at max load & I do not get any sign of bulging

    BUT - I can show you loads of primers that look like yours after decapping !


    Cheers

    Roy
    .

  9. #9
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    Thanks Roy.
    "I'm all in favour of keeping dangerous weapons out of the hands of fools. Lets start with typewriters." - Frank Lloyd Wright (1867-1959)

  10. #10
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    looks this way....would be better if you took a pic whilst still in the case.....looks like it was abit tight in the hole and required a bit more ooommmmph to decap
    Cheers

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