Any reason I can't use large rifle primers for my 7 Rem Mag and 300 Ultra Mag?

Discussion in 'The Ammo & Reloading Forum' started by bluesea112, Jan 3, 2008.

  1. bluesea112

    bluesea112 Active Member

    Joined:
    Nov 20, 2005
    Messages:
    1,326
    Location:
    West, TX
    I am about to begin reloading cartridges for my 7mm Rem Mag and .300 Rem Ultra Mag. I have a couple of thousand Large Rifle Primers, so I would prefer to use them instead of buying Magnum primers. Is there any particular reason I should not use Large Rifle primers in my magnum cartridges?

    Thanks for the help.

    Bluesea
  2. There most certainly can be, Blue. Magnum primers create a hotter, more powerful ignition jet and are necessary in most magnum caliber rifles for complete powder ignition. Go by whatever your reloading manual instructs you to use. My Speer manual calls for magnum primers in both the calibers you named for all powders listed.
  3. bluesea112

    bluesea112 Active Member

    Joined:
    Nov 20, 2005
    Messages:
    1,326
    Location:
    West, TX
    My manuels all call for magnum primers, and that is the reason I started to wonder if I could just use Large Rifle primers. I figured I would just add 1/2 gram of powder to the cartridges to make up for the primer difference.
    I have heard of fellows using magnum primers in large rifle cartridges, but I have never heard of the opposite. I guess the reasons you documented are why I have not heard of guys doing it.
    That rediculous $20.00 hazmat fee just rubs me the wrong way, but I guess I will just have to grit my teeth and take the beating.
    Thank you for the reply.

    Bluesea
  4. Mosin_Nagant_Fan

    Mosin_Nagant_Fan New Member

    Joined:
    Jan 18, 2007
    Messages:
    1,838
    Location:
    Montgomery, AL
    Well, either that or a lawsuit of the 6+ digit kind in the case something goes wrong.
  5. LDBennett

    LDBennett Active Member

    Joined:
    Dec 20, 2003
    Messages:
    6,291
    Location:
    Hesperia, CA
    Bluesea112:

    Adding more powder and using the large rifle primmers would make it worse!

    You need the Magnum (hotter) primers because a large case with lots of powder is hard to get started burning. The hotter primers assure better ignition. What the problem is, is a consistent burn from cartridge to cartridge. No matter the primer the cartridge will go off but with Magnum primers the burn will be more consistent from cartridge to cartridge increasing the accuracy potential for the load. There is the very slight safety risk (??) because of the possible incomplete ignition but it is really an accuracy thing.

    If you are paying the hazardous fee for every box of 1000 primers you are not doing it right! Try your local store where they buy primers by the cases and pay the fee one time for thousands and thousands of primers. I find that I can get Winchester primers for the least money at gun shows. There is always someone selling them for at least $5 a box less than the local stores. Also some seller on the internet include the Hazardous Materials fee into the price (don't charge you for it) but you usually have to buy in volume.

    Finally, until you are a seasoned reloader do not deviate from the recipes in the reloading manuals, for safety's sake. If they say use Magnum primers then do it. Which brand is not that important.

    LDBennett
  6. JLA

    JLA Moderator

    Joined:
    Feb 26, 2007
    Messages:
    18,236
    Location:
    Heart Of Texas
    +1 to what LD said, you dont want to catch a bolt in the face:eek:
  7. Popgunner

    Popgunner New Member

    Joined:
    Dec 3, 2005
    Messages:
    1,764
    There is no reason you can't use regular large rifle primers in any rifle cartridge right up to the 460 weatherby mag. You'll want to use a published starting load of course & the best manual for rifle loads all listed with regular primers is the second edition Lee manual. The only powder in the whole manual that's listed with magnum primers is Winchester's 296.

    "magnum primers were brought out in the 1960's by CCI & in their press release for them it states that their new "magnum" primers weren't made to be used necesarily in magnum cartridges but the real reason they made them was for use in all loads at low temperatures. If you look at the realy hard to ignite cartridges such as the .375 H&H mag & 460 Weatherby Mags they were brought out before there were "Mag" primers-the .375 H&H in 1912 & the 460 Weatherby mag in 1958.

    Any rifle load can benefit from mag primers in cold temps & mag primers can be substituted by reducing starting loads by 5% & working up again for loads calling for standard primers.

    Anyway there are perfectly safe published loads for any magnum cartridge using standard primers.
  8. JLA

    JLA Moderator

    Joined:
    Feb 26, 2007
    Messages:
    18,236
    Location:
    Heart Of Texas
    good to know, i got about 2000 magnum primers i was thinkin i was never gonna use, because my .303 loaded with AA2520 is the only one that calls for a magnum primer. thanx pop...
  9. ragtag

    ragtag New Member

    Joined:
    Jan 24, 2008
    Messages:
    3
    i have used regular rifle primers in my 300 win mag. just for shooting at the range and had good results. i would not add powder to make up for it. go with low and slow and work up. shoot away
  10. bluesea112

    bluesea112 Active Member

    Joined:
    Nov 20, 2005
    Messages:
    1,326
    Location:
    West, TX
    Thank you all for the replys. I really appreciate the information.
  11. whip

    whip New Member

    Joined:
    Jan 29, 2006
    Messages:
    242
    Location:
    Wyoming
    I would be a little hesitant in the 300 Ultra Mag. With a load of nearly 100 grs of slow burning powder I would perfer to use Mag primers for good ignition. Stick with the recomended components.
Similar Threads
Forum Title Date
The Ammo & Reloading Forum Reasonable spread? Apr 13, 2011
The Ammo & Reloading Forum Reasons why I reload Feb 8, 2011
The Ammo & Reloading Forum Ammo can still be found at reasonable prices Apr 25, 2009
The Ammo & Reloading Forum Some brass I can't identify Aug 26, 2013
The Ammo & Reloading Forum Some brass I can't identify Jun 17, 2013