Large Rifle vs Large Rifle MAGNUM

The #1 community for Gun Owners of the Northeast

Member Benefits:

  • No ad networks!
  • Discuss all aspects of firearm ownership
  • Discuss anti-gun legislation
  • Buy, sell, and trade in the classified section
  • Chat with Local gun shops, ranges, trainers & other businesses
  • Discover free outdoor shooting areas
  • View up to date on firearm-related events
  • Share photos & video with other members
  • ...and so much more!
  • Moorvogi

    Firearm Advocate
    Dec 28, 2014
    855
    I suppose the easy way to test this is to try it against a known load but I'm curious what others have found if they tried it.

    I'm looking to reload my 300 win mag and i found I don't have enough magnum primers to do a load test. I have enough non-magnum to go around for a small village though HAHA.

    What effects can I expect in using large rifle instead of large rifle magnum primers? I "assume" it's very similar but i've never tested it. I've seen some loads that list magnum primers in non "magnum" rifles though i never tried this combo.

    I'm not going to hold anyone liable for actions blah blah blah. Nor should anyone else try it saying they saw it online.. etc etc.

    I'm going to wait for magnum primers but what are the realistic potential outcomes? Lower FPS, pipe bomb... unicorns farting rainbows?
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    Hang fires, lower pressures and velocity, failure to ignite, would be more common. I like the coolest primer that will get the job done. Palma shooters will use small rifle primer brass to set off 46 grains of varget. But...in cool weather its iffy. But with a 300 win mag, that's lots of slow powder. I'd use magnum.
     

    Moorvogi

    Firearm Advocate
    Dec 28, 2014
    855
    I will let you know next Saturday.
    I am loading a bunch of 6.5 Grendel and will be experimenting with a dozen small rifle primers vs the small rifle magnum primers across my chrono on Friday afternoon. Everything else will be identical for the experiment.

    i'm not sure how to test the hang fires, other than using slow motion recording on your phone. pointing it at the trigger finger and listening for the bang bang noise. very crude but might work.

    i'm interested in FPS and POI shifts. If they are the same or different but consistent... meh.
     

    Melnic

    Ultimate Member
    MDS Supporter
    Dec 27, 2012
    15,282
    HoCo
    for reference
     

    Attachments

    • primer energy.jpg
      primer energy.jpg
      49.3 KB · Views: 545

    Doco Overboard

    Ultimate Member
    Primers should be able to ignite all the powder space simultaneously as much as possible not just the powder that has accumulated near the flash hole. In a low order of ignition the flash may only penetrate the powder column so far which means in turn it will take grains of powder burning to completely ignite the rest of the charge. In a large case the problems will be inconsistent velocity, poor accuracy or an occasional hang-fire in a very large case which can also lead to detonation.
    Something else to consider is that a certain amount of thermal energy is lost in what may be considered large cartridge cases like 3006 and up due to the size of the case and the cooling effect with contact of the chamber walls.
    Primer efficiency is determined by the powder composition and granulation of the powder, volume and shape of the cartridge and heat generated by the explosion of the priming compound. It is also known that strong primers in small cases can be the cause of poor accuracy, high and erratic pressures with some but not all powders 4759 being one of them which is why its popularity I suspect is on the decrease if its even manufactured anymore.

    I used 4320 in a Remington magnum case with LR primers and experienced the above some years ago. The chamber however did not headspace on the shoulder but entirely on the belt which may have been contributory to the problem to a certain degree. Accuracy was affected until the rifle became warmed and then settled down but never satisfactorily. Obtaining WLRM's solved the problem for me.
     

    Postell

    Banned
    BANNED!!!
    Nov 5, 2018
    291
    Hang fires, lower pressures and velocity, failure to ignite, would be more common. I like the coolest primer that will get the job done. Palma shooters will use small rifle primer brass to set off 46 grains of varget. But...in cool weather its iffy. But with a 300 win mag, that's lots of slow powder. I'd use magnum.


    I load a few thousand 300 Win Mag rounds each year, Only one load uses a mag primer.
    Please post the data that shows what you are posting please.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    I posted some info over on the CMP Forums (I will put it here later), but testing found that going from the coolest LR primer to the hottest LR Magnum, upped the pressure by 12,800 psi.

    Basically your data from using LR primers will be at best worthless, and at worst dangerous, when switching to Magnum primers.
     

    E.Shell

    Ultimate Member
    Feb 5, 2007
    10,244
    Mid-Merlind
    I posted some info over on the CMP Forums (I will put it here later), but testing found that going from the coolest LR primer to the hottest LR Magnum, upped the pressure by 12,800 psi.

    Basically your data from using LR primers will be at best worthless, and at worst dangerous, when switching to Magnum primers.
    Yep, definitely cannot switch primers on an established load without expecting a marked change in performance.

    Magnum primers are usually recommended for large capacity cartridges using slower powders, but that is a recommendation, not a law. Regarding whether they are needed or not, one can discuss theory all you like, but without testing, you just don't know.

    I found that Winchester standard Large Rifle primers were just a little hot, and I could not get my .308's SD numbers down with them. CCI 200 and Fed 210s worked fine. Using hotter or magnum primers in loads that do not need them can be detrimental to performance, in terms of accuracy or consistent velocities.

    I had a 6.5-300 Weatherby that burned 86 grains of H870, or almost that much Retumbo. In theory, these loads clearly REQUIRE a magnum primer, but my best accuracy and SD numbers came with using standard LR primers.

    Once one gets their head around the fact that magnum and standard primers cannot literally be interchanged without working up a load, safety concerns are no longer an issue and it depends on the desired performance. Cold weather and slow powders in big cases typically call for magnum primers, but it will depend on your load.

    Military primers, like CCI#34 and #41, in addition to their slightly harder cup, are more like magnum primers in brisiance, to enhance all-weather reliability.
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    Here is the link - https://www.chuckhawks.com/primers.htm

    Here is the relevant portion:

    The A-Square Company conducted pressure tests involving six different primers. These tests used the 7mm Remington Magnum cartridge with a 160 grain Sierra BT bullet and 66.0 grains of H4831 powder and the results were reported in the A-Square reloading manual Any Shot You Want. A-Square used CCI 200 and 250, Federal 215, Remington 9 1/2M, and Winchester WLRM and WLR primers in these tests. They revealed a total spread in pressure of 12,800 psi from the mildest standard (the CCI 200) to the hottest magnum (WLRM) primer tested.

    A later comment from that thread stated - "For IMR4831, that A-Square number represents about a 5.7% increase in powder charge."

    Would you jump a powder charge by 6% in one step?????

    If you know, OCW that is two accuracy node levels above your current load.
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    I load a few thousand 300 Win Mag rounds each year, Only one load uses a mag primer.
    Please post the data that shows what you are posting please.

    Wow, a few thousand per year? What are you seeing for barrel life. Let me look for links, but most of my books are packed away that show this.

    However your few thousand a year comment leaves me scratching my head as much as mine does yours. While I'm looking up the links, I'd like to hear more about the type of shooting your doing that allows you to shoot a big boomer that much.

    But think about this, other posters said switching from a standard primer to a mag without working up is foolish because pressures, then that collaborate than standard primers are LOWER pressures loads if powder charge, bullet, chamber, and internal volume are the same.
     

    Park ranger

    Ultimate Member
    Dec 6, 2015
    2,315
    cartridges based upon that cartridge case.*

    Within each are standard and magnum primers. Standard primers are for cartridges of moderate capacity and velocity. The powders in these cartridges readily ignite. Many magnum cartridges used large charges of very slow burning powders that can be difficult to ignite, especially in colder weather. These cartridges utilize a magnum primer with a more explosive priming compound that generates a hotter and more voluminous fire.

    https://www.americanrifleman.org/articles/2018/1/15/back-to-basics-primers/

    And here people are discussing hang fires with big magnums in cold weather just like what happens to some palma shooters in colder weather with small rifle primers with only 46 grains of varget, like I said earlier.

    https://forum.nosler.com/viewtopic.php?f=4&t=1651

    Another good article

    https://ozgunlobby.com/t/choosing-the-right-primer/720
     

    Pinecone

    Ultimate Member
    MDS Supporter
    Feb 4, 2013
    28,175
    That's neat. I don't fully understand the significance of the numbers, other than for comparison, but I'm surprised how little difference there is between rifle and rifle mag (on both sizes). :shrug:

    That does not matter.

    What matters is the possible pressure increase when switching primers.
     

    Postell

    Banned
    BANNED!!!
    Nov 5, 2018
    291
    Wow, a few thousand per year? What are you seeing for barrel life. Let me look for links, but most of my books are packed away that show this.

    However your few thousand a year comment leaves me scratching my head as much as mine does yours. While I'm looking up the links, I'd like to hear more about the type of shooting your doing that allows you to shoot a big boomer that much.

    But think about this, other posters said switching from a standard primer to a mag without working up is foolish because pressures, then that collaborate than standard primers are LOWER pressures loads if powder charge, bullet, chamber, and internal volume are the same.

    I'm not scratching my head at all with what you posted, I just have never seen it with my 40+ years of reloading for 300 win, thats why i'm asking for data.
    I shoot a bunch with two other ya ya's at a couple of over 1,000 yd clubs and one a few hours away in Ky thats 1,650. I can get past 1,000 at my weekend place in southern IN. When we all have time we hit the F Class matches within 150 miles of so, two of us are business owners.
    I use sierra 190's in Fed Mil cases pushed with a standard Fed 210 and a compressed over manual load, I am also an avid Quickload user.
    I shoot two old Rem 700PSS's and a 700 single shot 40X short action sitting in a McMillian.
    All get rebarreled at the most every two-three years with the throats being trash by then.
     

    Jerry M

    Ultimate Member
    Jun 13, 2007
    1,688
    Glen Burnie MD
    Primers have been a PIA for me.

    I had a 6.5 Rem Mag that I tried the Nosler recommended powder Reloader-19. I got hang fires with CCI and Remington LR primers. Winchester LR primers (silver ones) and CCI Magnum did fine. I then developed a load for it with (now discontinued) AA-3100 powder using the Winchester LR primers (silver ones). I ran out of those primers and switched to the new Winchester LR primers (brass colored ones). I tested the load, with the new primers and it was safe in this rifle. So I loaded about 600 rounds. I also loaded about 200 .30-06 with these primers.

    Halfway through an F-class match I start blowing primers left and right. Turns out that these primers were defective. Skirts were blowing out. Had to pull almost 500 bullets, dump the powder, reprime, and reload. Had the same problem with the .30-06 loads. Switched to magnum CCI in the 6.5 RM and regular CCI primers in the 06 without further issue.

    On the other hand, I had a 7mm Rem Mag 40X that I used AA-3100 with CCI Bench rest primers. I tested them at 600 yards the magnum CCI and regular CCI LR primers loads were within one MOA. I just kept using the BR2. Shot it out to 1,200 yards, but never below 32 degrees. When I would experiment with other powders I always used a magnum primer.

    But if in doubt with a .300 WM use a magnum primer.

    Good Luck

    Jerry
     
    Interesting Update

    Yesterday, I took some hand loads up to Moorvogi's farm and ToolAA was still there from the morning session. My go-to 6.5 Grendel load is as follows: Hornady brass, Midsouth 100gr Match Monster/Nosler Custom Comp, 30.2gr 8208XBR, and CCI small rifle magnum primers, 2.20" OAL
    I also made a dozen matching rounds, but used CCI small rifle (not magnum) primers.
    We ran these past ToolAA's Kestrel Lab Radar and the rounds with magnum primers averaged ~50fps slower than the rounds with standard primers. I have no idea whether there was a pressure difference, but there was a clear difference in velocity. The three of us all witnessed this and were scratching our heads. We expected the opposite.

    ETA- 10rds of each primer were chronographed, so it was a legitimate observation.
     

    Uncle Duke

    Ultimate Member
    MDS Supporter
    Feb 2, 2013
    11,667
    Not Far Enough from the City
    Counterintuitive I know. But it would seem that the higher brisance primer, when detonated in combination with this particular powder, is affecting the resulting peak pressure or the pressure curve in such a way that it actually reduces velocity. As you mention, you have no way of measuring pressure. The "why" thus remains a matter of speculation. But arguably another reason to stick with industry published recommendations IMO, as they can indeed make those measurements.

    As an aside, I have documented (infrequent) instances of this phenomenon occuring with increases in powder charges as well, where one would expect the exact opposite.
     

    Doco Overboard

    Ultimate Member
    Primer charging is done by a skilled worker who squeegees and smears the still wet priming compound onto a perforated sheet. I could see where some inconsistencies could result from the entire sheet not being smeared the same way every time before the cups and foil and anvils are finally booked together then allowed to dry.
     

    Users who are viewing this thread

    Latest posts

    Forum statistics

    Threads
    274,926
    Messages
    7,259,325
    Members
    33,349
    Latest member
    christian04

    Latest threads

    Top Bottom