What's dif. twixt rifle & pistol primers, really?

Discussion in 'The Ammo & Reloading Forum' started by dartswinger, Feb 16, 2010.

  1. dartswinger

    dartswinger Member

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    Past weekend I was at friends house as he loaded around 100 45acp rounds for our Sunday shoot'em-up. He was out of lge. pistol primers so he just used lge. rifle primers claiming they're all the same actually. He was loading 4.5gr Bullseye and 225 cast bullet. Went shooting Sunday and all worked normal, nothing blew up. Is there really any substantial difference here or is the 'designation' just a marketing gimmick?
  2. RustyFN

    RustyFN New Member

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    Small rifle primers are the same size as small pistol, just hotter. Large rifle primers are a little taller and hotter than large pistol primers.
  3. jdon72

    jdon72 New Member

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    The guy got lucky this time...usually the rifle are hotter and everything else rusty said. According to the book, he backed off on the total powder charge from bullsyes' max load...not saying that is ok. I personally would not do it. Be careful, all it takes is one mistake...

    J
  4. madmantrapper

    madmantrapper New Member

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    Are you saying you always use the max charge?
  5. jdon72

    jdon72 New Member

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    Not at all...I am saying that 4.5 grains is around 20% less than the max charge. Personally, I do not use the max charge on a normal basis for any of my loads. On pistol, I have loaded some max charges and use them for hunting. I prefer a little less than the max charge in my 10mm and 45. But using a rifle primer will only ignite the powder faster and create more pressure build up faster in the cartridge. These guidelines we use in any of the loadbooks are specific for certain items and changing to rifle primers is like mixing powders of different burn rates....I personally would not do it.

    J
  6. Gearheadpyro

    Gearheadpyro New Member

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    As stated above, rifle primers are generally hotter than pistols. Although I do not recommend it personally, some do load rifle primers in pistol cartridges with reduced powder charges.

    DO NOT load pistol primers in rifle cartridges! One of the other primary differences between the two types is the thickness of the cups. The rifle primers are made to handle higher pressures that will blow pistol primers out.

    I'm with Jdon72 on this one, follow what the manual says. They do a ton of R&D on this stuff all to keep reloaders safe. IMHO, ignoring it is foolhardy.
  7. bntyhntr6975

    bntyhntr6975 Member

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    Something else to add in: with the rifle primers having a thicker cup, this also makes them "harder", requiring a little stronger blow to set them off. I am not sure if there is a height difference betwen SR and SP, but the LR and LP are slightly different. So, you would also be taking a chance with a primer sitting flush in the pocket rather than slightly recessed. With a little common sense, you can substitute primers, but it is not recommended. If the SHTF, a person may need to do it. But, until then, there is really no need. Last but not least, I do agree with following the manuals whenever possible.
  8. Terry_P

    Terry_P New Member

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    The pressure curve is something I don't totally understand but I do know that it isn't always linear. Sometimes a small short spike can increase the pressure exponentially. In other words it turns your hand into a bomb. If you are out of a primer that the books call for then go buy some. They can be scarce under Obozo but they are out there. Don't substitute unless it has been proven by those that do the testing that you can.
  9. jdon72

    jdon72 New Member

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    I just happened to be looking on CCI website and found this...

    Q: I have CCI Large Pistol primers, can I use then instead of the Large Rifle primers that I need to load for my rifle loading?
    A: This is not adviseable, the primers are dimensionally different as are the primer pockets.
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