Magnum primers in standard cartridges

Until now, I have only used magnum primers in magnum cartridges and standard primers in everything else. However, due to the component drought I find myself with a significantly larger amount of magnum primers. I know others have used magnum primers in standard cartridges and thought I might give it a try. My thinking is this would allow me some range time without completely exhausting my standard primer supply.

My main question is, how do you determine how much to reduce the powder charge when changing from standard to magnums? I know pressure increases with magnums so do you reduce 10% and work up or drop back, say, 2 grains and go from there?

Any input and/or suggestions would be greatly appreciated.

Ron

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I would drop another .5 grains if using the magnum primers and work up from there.

Are your Loads at max or below? If I am at max I drop a grain or two, if that much or more below I just switch to mag primers.

Tjay, I don't run max loads in my my rifles, regardless of caliber. Normally, I allow at least a grain less than max.

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I just load them up. I use mag primers for all my loading. Never had a problem and use a lot of max loads in many different cartridges

Speer uses them with ball and spherical powder.

I was surprised of the results in my 06. And even more surprised of what certain primers do over others. Fliers and erratic groups tighten up nicely with a bedded action of course, and a floating barrel.

https://www.6mmbr.com/primerpix.html Primer Flash Test Photos

Pictures are worth 1000 words, ain’t they slickrem?

Unfortunately….. I’ve never had great luck shooting words out of any of my rifles. When it comes to actual shooting, I prefer Mag primers in all my loads that use more than about 40 grains of powder. Consistency leads to accuracy….. and Mag primers are more consistent over a broader range of temps and charges than standard primers are. This leads to lower AVERAGE ES/SD numbers over a larger spectrum of hunting/shooting conditions…. making them more “accurate” overall. Especially when you could be shooting at critters when it’s 80+ degrees…. or -20 degrees.

A couple of weeks ago I was able to pick up 2 new bricks of mag primers for $48 per brick, I just shoot LR, not mag primers, but I was darn happy to have them added to the reserves in these times.

I don't shoot any large capacity cartridges and never seen results that would make me think I needed mag primers, but I knew I could use them just fine. If/when I use them, a couple of my loads in a few rifles will be adjusted down first out of precaution, other than that I'll use them just like any other primer.

I’ll reiterate ShadeTree. I use both without issue no matter the cartridge. The only difference I’ve seen is with heavy charges with really slow powders. LR primers can make very slow powders at heavy charge weights seem like they are a little slower burning than main stream magnum powders. Other than that I have seen no difference between magnum or regular LR primers with regards to performance or accuracy. LR primers will go bang in large capacity cartridges as well as magnum primers with accuracy and consistency. Magnum primers have shown no advantage for me unless powder charges are above 75 grains or so in long action cartridges. I’ve seen no difference at all in short magnum applications.

Joec7651":5d7pzrgu said:

I’ll reiterate ShadeTree. I use both without issue no matter the cartridge. The only difference I’ve seen is with heavy charges with really slow powders. LR primers can make very slow powders at heavy charge weights seem like they are a little slower burning than main stream magnum powders. Other than that I have seen no difference between magnum or regular LR primers with regards to performance or accuracy. LR primers will go bang in large capacity cartridges as well as magnum primers with accuracy and consistency. Magnum primers have shown no advantage for me unless powder charges are above 75 grains or so in long action cartridges. I’ve seen no difference at all in short magnum applications.

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what accuracy do you get without mag primers verses standard primers? post some target results.

My accuracy improved with mag primers with Spherical powders.

slickrem":1zypn219 said:

Joec7651":1zypn219 said:

I’ll reiterate ShadeTree. I use both without issue no matter the cartridge. The only difference I’ve seen is with heavy charges with really slow powders. LR primers can make very slow powders at heavy charge weights seem like they are a little slower burning than main stream magnum powders. Other than that I have seen no difference between magnum or regular LR primers with regards to performance or accuracy. LR primers will go bang in large capacity cartridges as well as magnum primers with accuracy and consistency. Magnum primers have shown no advantage for me unless powder charges are above 75 grains or so in long action cartridges. I’ve seen no difference at all in short magnum applications.

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what accuracy do you get without mag primers verses standard primers? post some target results.

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Read it again Slick…… he clearly states he seen no difference at all in short Mag applications.

All this stuff is pretty easy….. if you actually shoot.

I don’t take pictures of every group fired. I have and use Winchester, CCI, Federal, and Remington primers in both standard and magnum flavors. Your experiences may be very different than results I’ve had.

No 2 rifles are the same, just as no 2 people load with the exact same procedures. I’ve seen no difference in performance in all but very heavy slow burning charges. Also bare in mind that all Winchester priming compounds are formulated to ignite ball powders efficiently because Winchester powders are ball propellants. A WLR primer designed for ball applications (which all Winchester primers are) will ignite slow extruded powders just as effectively if not better than some magnum primers. CCI priming compounds burn hot but produce low brisance, which ignites both fast and slower burning powders perfectly, Federal primers burn even hotter but also with lower brisance, while Remington primers are also very hot with the added advantage of very high brisance. All have different qualities and will ignite any powder without fail, more consistently than either you or I can shoot.

I get great results with both. Some of my magnum loads are actually more accurate and consistent with standard primers. Some are not. IE no 2 rifles are the same.

There is also the practice of some long range bench rest shooters that win championships using larger capacity cartridges with small rifle primer pocket brass to in fact achieve more consistent ignition and burn rates for their particular load. After they are awarded their trophies and purse, perhaps someone should introduce them to LRM primers.

I very much enjoy seeing people achieve success and accuracy with their loads. There is also a well known individual that stated that “the only interesting rifles are accurate rifles”. Without doubt if you achieve the best results with magnum primers, then use magnum primers. If it ain’t broke don’t fix it. I am being 100% honest when I say that I wish you many accurate, enjoyable, and satisfying days afield with interesting rifles. That’s why our sport and this group is so grand. We share friendship, experiences, and knowledge to make each other better marksmen and loaders.

Good info Slick. However burn rates of primers will change from cartridge to cartridge just like a powder will have different burn characteristics from cartridge to cartridge. There are many variables. Charge weight, case fill, long or short action, light or heavy bullet, case capacity, and the list goes on.

I used WLR with ball powders, and magnums did a better job. Way less pressure spikes. Fliers went away. Best I can tell you.

I’m not doubting your word at all. It’s great that you found a load that works well for you. It takes a good bit of work to find the combination that the rifle likes. I use WLRM for US869 loads I’m working on. Haven’t quite found “it” yet with that one. Thinking about just buying a 28 Nosler to make load work up easier with the powder. Lol.

yeah I found it to be more informative and selective when selecting powders, for certain cartridges.

slickrem":bsmhjkn2 said:

yeah I found it to be more informative and selective when selecting powders, for certain cartridges.

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Forgive me but I’m not following. I’m not sure what you found more informative. You can always teach an old dog new tricks, and I’m always open to suggestions that make load work up easier or take less time.

BTW, as a side note does anyone know of anywhere to find RWS rifle primers possibly after this latest shortage has subsided?

sorry worded it wrong. I like to be more informed before selecting a powder.

Have no fear. I’m informed enough to get the group where I want it. The HBN coated 180gr Bergers are looking pretty promising with the US869 in my 1:8 rifled 7RM. I haven’t started any load work for them in my 1:9 7RM. So I can’t say anything about that one yet, but it seems to shoot most anything you feed it well.

My first round of load work up got three round groups into .72” barely shy of 3000 fps at 100 yards. I think I’ll be able to pull them together with a little more time at the bench. No pressure indications thus far so I’ll get the charge weight dialed in, then use seating depth for final tweaking of the group. Although with the SD’s in the low teens I may just work with seating depth. That’s enough velocity with 180’s to be more than adequate for anything I would would hunt with a 7RM. It’ll come together, just takes a little finesse. You know how it is Slick. :roll:

I forgot. One nice thing is that the Berger 180’s seem to produce less pressure than the 175gr ELD-X due to the Hornady’s longer bearing surface. The Berger’s also seem less temperamental than the ELD-X’s. I was able to get 3003 fps from the Hornady’s with RL25 and tiny groups. I think I still have a pic of that group from a previous post on that load. I’ll have to check. I’m not sure though.