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Thread: Primer use

  1. #1

    Primer use

    Hello all, can I have your oponions on the use of magnum primers in non magnum calibers, when loaded with slower burning powders.Thanks in advance.

  2. #2
    Quote Originally Posted by Hunterjohnb View Post
    Hello all, can I have your oponions on the use of magnum primers in non magnum calibers, when loaded with slower burning powders.Thanks in advance.
    magnum primers will burn hotter and increase pressures in non magnum cases so reduce loads by 10% and work up again. Personally i would only use a magnum primer in a magnum case

  3. #3
    Quote Originally Posted by accurate View Post
    magnum primers will burn hotter and increase pressures in non magnum cases so reduce loads by 10% and work up again. Personally i would only use a magnum primer in a magnum case
    Define magnum case .

    An example:- I brought a tub of Reloader 19 and made up some rounds to try in 25-06 using my normal Rem 9 1/2 or CCI 200 primers and got some hang fires . I had also loaded up some .270 Winchester with Sierra 140 BTHP bullets from the same tub and using the same primers ........................... shot fine. Repeated the 25-06 recipe and got hang fires again in it .................... So tried the load with some CCI250 primers and the load fired fine in the 25-06 using the same tub of Reloader 19.

    Now neither the 25-06 not the 270 Winchester are magnum cases yet they use more Reloader 19 than the .240 Weatherby Magnum for instance does and that is a belted magnum case ............................... so define a magnum case .

    Now Hunterjohnb really the only thing to do is to try and see which your rifle prefers. Just take it slow and work up as per normal hand loading safe practice .

  4. #4
    I have used them with good results in the 6.5x55.
    I never found any increase in pressure but I would still reduce loads and work up to be on the safe side.

  5. #5
    i shoot 270 and from september 1st untill april i always use a mag primer and always remington never had a problem i think the powder burns a lot better/cleaner when the weather is a bit cooler

  6. #6
    reduce load by 10% and work up with magnum primers.
    i use magnum primers with
    100gn spbt in 243
    150gn spbt in 308
    250gn spbt in 338

    they burn hotter and longer so they burn most of your powder but do look out for presure signs.
    I`m afraid when i die the wife will sell my gear for the price i told her

  7. #7
    Quote Originally Posted by mick b View Post
    reduce load by 10% and work up with magnum primers.
    i use magnum primers with
    100gn spbt in 243
    150gn spbt in 308
    250gn spbt in 338

    they burn hotter and longer so they burn most of your powder but do look out for presure signs.
    So, when you dropped back by 10% to find a load for the magnum primers, I assume you ended up with a lesser powder weight than when you used conventional primers?

    If this was the case, did you still achieve the same velocities (more/ same / less)?

  8. #8
    yes you do end up with less powder and yes velocities are higher,you have to work the load up at .2 at a time and to watch for presure signs.
    what cal are you loading?
    I`m afraid when i die the wife will sell my gear for the price i told her

  9. #9
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    Primers are as much a variable component as any other in reloading and canalter velocity and trajectory and therefore accuracy quite considerably.

    I have long been an advocate of using primers in the same way aspowder to vary a load with great effect.

    We dont choose our case because one looks shinier than another but because ofthe chemical composition that is most suitable for our particular load. Neitherdo we choose a Powder just because the local shop has it on the shelf and sowith Primers - choose your primer to do the best job possible for the load youare generating.

    A change of primer can in some loads require a drop of 3 grains and thedifference in velocity without any increase in pressure can equally improve by100fps. Use your primers in the same way as your powder and you will besurprised at the difference your loads will provide.

    Here is a basic heat chart - from top to bottom drop about 5-6% in powder andwork from there.


    http://img.photobucket.com/albums/v356/mry716/Shooting%20-%20other/primerheatchart.jpg


    Use it as a guide and add in your own primers when you have assessed them. eg,the Prvi Partizan Primers although burning approximately as hot asthe Winchester range do because of their different construction not seemto require a reduction in powder when changing from say Remington. Try foryourself and let us all know your test results as it will expand the abovechart considerably.

    Use of Magnum primers is normally reserved for the Ball Powders but I amfinding I can use them to great effect in the shorter stumpier cases suchas the WSM and WSSM range of cartridges. Logically this should also be validfor the Benchrest PPC cartridges.

    The same is true for the H4831 SC powder in 243 - A Federal Magnumprimer seems to provide anything up to 120 fps higher velocities thanstandard primers yet seemingly without additional pressure.
    BUT
    do drop the powder weight and build up again.



    Please remember to drop powder weights when changing primers and do alsoremember that with hot summer weather you need to reconsider all those maxloads and take out a little powder.

    A 10 degree rise in temp requires a 5% decrease in powder. If we are going toget such varied weather in coming years it may be best to have a min, intermediateand max load to use dependant on weather temperature.


  10. #10

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