difference in primers?

Discussion in 'Reloading' started by Wheatgerm, Apr 4, 2013.

  1. Wheatgerm

    Wheatgerm Well-Known Member

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    Currently I use cci large rifle mag primers but due to not being able to find them anywhere I was wondering how much it COULD effect my load to switch to another brand of magnum primer? Thanks in advance
     
  2. Greyfox

    Greyfox Well-Known Member

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    Generally, I don't see much of a difference , if any, in accuracy between the Cci and Federal magnum primers in accuracy. I have experienced differences in ES when changing primers. I have more frequently seen differences using standard primers in my 308 when changing brands. Overall, I'd say it's a crap shoot and the only way to find out with your specific load is test the different primer. I'm doing this right now with my 308 target rifle. This component shortage is murder.
     

  3. Wheatgerm

    Wheatgerm Well-Known Member

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    I should have just got a box of 1000I while I had the chance lol. If I do switch primers should I back the load off? Im not at max anyways, not showing any pressure on the primers. Will different brands show different pressure?
     
  4. Greyfox

    Greyfox Well-Known Member

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    I personally wouldn't bother if you weren't at max pressure. I have never had a primer change put me over pressure given they were all LR primers, and not interchanged with magnum primers.
     
  5. Wheatgerm

    Wheatgerm Well-Known Member

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    Well thanks for the quick help I wasn't thinking it would change much besides possibly a little accuracy if any at all.

    Of anyone has any warning about it please share, besides that ill just get what I can find in the same sizes and hope for the best. It sucks its like this but im sure we're all feeling the same pressure
     
  6. ChrisAtl

    ChrisAtl Well-Known Member

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    I'm not an advanced reloader however I would be somewhat cautious switching primers. I saw a video or maybe a series of photos online showing the different brands of primers grouped together by size/type. They certainly did have very different flame and heat signatures. This will likely cause the powder to ignite and burn differently.
    Everyone I am sure is feeling the crunch on ammo and components right now. I'm hoping it eases soon. There are plenty of items I would like to buy but I'm waiting to order when I can get it all in one order. The haz mat fee will kill you on four separate orders as opposed to one larger order...
    I will try and see if I can find the primer comparison photo and ill post it.
    Good luck and post your results if you can because I'm sure plenty of people will be interested.
     
  7. kcebcj

    kcebcj Well-Known Member

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    If you are nervous about it back off two grains from your standard load. Put together 5 at 1/2gr increments and bang back up and check. When I change primers with any load I do just that. Seems like a waste of time and material but I don't take chances with stuff that blows up and could create some fairly expensive problems.

    The standard recommendation is to reduce by 10% and work back up. I just don't go that far back.
     
  8. ChrisAtl

    ChrisAtl Well-Known Member

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  9. Gene

    Gene Well-Known Member

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  10. old_heli_logger

    old_heli_logger Well-Known Member

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    Federal primer cups are softer too, so it might look like you're getting more pressure.
    I'd back off a little powder and redevelop your load.
    Good luck!
     
  11. Wheatgerm

    Wheatgerm Well-Known Member

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    I understand for safety about backing off... but where powder is impossible to find and also bullets, it maybe easier to just wait for the primers I have always used rather than working up the ladder test lol. A year ago I never would have second guesses going out and trying to perfect the load. Now days it seems I hope for lass than 1" groups and call it good just so im not dumping precious resources away
     
  12. Nalgi

    Nalgi Active Member

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    As explained in Barnes Univ.; if you are throwing loads over 60 or so grains you will get a more efficient powder burn with a magnum primer, therefore more velocity because you burned more powder in the cartridge case.

    Put another way; The more powder you can burn in the cartridge case the more gas pressure will be created and the more velocity you will generate.

    This is why WSM cartridges generate the same velocities with 12% less powder.

    The powder is strung out the length of the cartridge case as it lays parallel to the earth (like on a shooting bench). The longer the "line" of powder, the longer it takes to burn. Once the gas pressure is sufficient to pop the bullet out of the crimp, the burn rate of the remaining powder drops big time. There are some interesting test result on the web showing this relationship.

    Take a 300 WSM cartridge and a 300 win mag cartridge and lay them on a table. Its easy to understand that the powder in the 300WM would take longer to burn than a 300WSM due to the length of the "line" of powder, even though we are talking mili sec.
     
  13. SidecarFlip

    SidecarFlip Well-Known Member

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    Something I've found too be true (from fiddling with muzzleloaders and changing the physical attributes between the primer itself and the breechplug face) is that different brands of primers are actually different overall lenghts and vary by a couple thousands between brands.

    This becomes especially critical when reducing the breechplug face to firing pin retainer clearance in an inline muzzleloader to reduce primer blowby and increase powder burn. Get to too tight (too little clearance and you get a slam fire when closing the action or change brands of primers and a taller primer causes the same scenario.

    Which is why I stick with one brand (CCI). Cup diameter also varies a bit from brand to brand but the diameter varience is much less than overall height. Cup diameters vary a couple 10ths.

    I've heard that one should always seat primers to the bottom of the pocket but I only seat my primers (in cartridges) flush with the casehead and no more. As widely proven, primers that are proud of the casehead can cause slam fires and rule of thumb is 1-2 thousands below the casehead, but again, I seat level with the casehead.

    At least in my perspective, sticking with one brand and quality (benchrest, magnum or regular) goes a long way towatd shot after shot repetability.

    I realize that with the component availability being what it is, that may not be practical but I would strongly suggest working up the load again, if you change brands of primers or the quality in the same brand.