Easy Primer Question

Discussion in 'The Ammo & Reloading Forum' started by Squeak, Dec 17, 2011.

  1. Squeak

    Squeak Member

    I just found out that "small" rifle primers are the same physical size as "small" pistol primers. That leads to my question. Are "large" pistol & rifle primers the same physical size?
    I know that rifle is rifle & pistol is pistol and even though they might be the same dimensions, they are not interchangeable.
  2. muddober

    muddober Active Member

    Sep 19, 2008
    Carson City Nevada
    Squeak, you bring up an interesting question and I will probably get in trouble here because there are so many opinions and ideas on the subject. Large rifle and large pistol are the same size. It is my understanding that the major difference between the two is the skin thickness. Rifle primers are thicker so as to prevent the primer from being pierced by the rifle firing pin which usually hit harder than most hanguns. Also the rifle primer thicker skin means that the primer seats with more friction making it less likely to back out under pressure.

    I have interchanged the two in a pinch with no noticable differences. The 454 Cashul calls for a small rifle primer and I use large pistol magnum primers in my 30 Herret.

    Last edited: Dec 17, 2011

  3. Skipper

    Skipper Well-Known Member

  4. X Ring

    X Ring Active Member

    Mar 23, 2011
    If you were to use LP primers in a rifle, they would seat too deep in the pocket and one of two problems "could" occur.
    1) Light firing pin strikes, primer may not go off
    2) Cup could pierce sending gas back into firing pin causing damage.
    If you were to use LR primers in a pistol the primer would no seat flush with the case head and the action of the slide "could" set the round off before it was fully chambered. NOT good.
    Nither is worth the risk.
  5. Boris

    Boris Former Guest

    Oct 1, 2010
    Back when I had a NEF 357 mag rifle I had a load with a Hornady 200 grain .358" JSP RN I loved to wack deer with. The leade was long enough in the chamber I could load them to the crimping groove. Odd looking final loaded round to say the least. I used to load it with CCI small rifle primers and they always seated flush for me.

    That was a good load too. With open sights I got just over 2" groups at 100 yards and deer just loved to drop about two feet straight down for me to ease filling the freezer for me lol....
  6. Alpo

    Alpo Well-Known Member

    Feb 3, 2007
    NW Florida
    Boris, small rifle and small pistol are the same physical size. The difference is in how they are made - the thickness of the cup and the power of the charge.

    Large pistol and large rifle are not the same size. As Skipper and Xring said, LR are longer/taller than LP.
  7. Boris

    Boris Former Guest

    Oct 1, 2010
    Ah, gotchya. Never tried to interchange them two. My dads 45LC rifle always worked great so I never seen a need to try. Guess I woulda learned the hard way lol.
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