Large Rifle/ LG Magnum Primers?


Well-Known Member
Oct 23, 2009
A friend of mine told me the other day that you can use large rifle primers in magnum cartridges. Is this true?
But they will work?

The three calibers that I load are 7mm RM, 7mm SAUM, and 270 WSM. Now with all of this magnum stuff going on, what kind of primers do you think I use?

The long 7mm RM cases get F 210 or WLP.
The two short cases (270 WSM and 7 SAUM) get WLP or CCI-200.

In the winter I use the hotter primers and in summer the cooler ones.

I think that if my primer is not hot enough, my extreme velocity spread will increase. If my primer is too hot, I'll see more fliers.
Your mileage may differ. :D

Hope this helps. See what works for you.

JM .02
I nearly always try both in a cartridge, some times it gets rid of that one flyer that screws your group or your ES. I find a decent load with a mag primer then load three rounds of each primer and test, the last one I did one primer put the load at .360 one was .440 till it flung one to 1.5 then the others were 1.5in triangles, I then bought as many of the one that I could find.
I have hunted with both Magnum primers, and non-magnum primers in a 300 Winchester Magnum and Reloader22 in temps below -30c (-22f) without problems. I've always used what ever primer gave the best groups for the load I was using. Now if I was using 70+ grains of a ball powder in that cold of weather I might want to go with a magnum primer..

With Reloader22 I lose about 150 FPS from +20 to -20c (68f to - 22f) and adjust my loads accordingly. I'm thinking of trying a less temp sensitive powder next year but don't want to leave R22 as it's always given me great accuracy, and velocity in various calibers.
you're going to be in the neighborhood of 90+ grains of powder.

That's magnum country. I wouldn't even think of using large rifle primers for that much powder.

Why not just buy some magnum primers?
Believe in most cartridges it comes down to three elements; cartridge {capacity} size, powder {type} burn rate and weather {hot or cold} temperature. These three seem to influence whether you should use {magnum or standard} primers in your reloads, more often than some of the other factures that might come into play.
Just my .02

It is a 300 rum i was using rem 9.5 primers before and all i have is win large rifle

You can always just try it, but my guess is you need mag primers for this cartridge. Check gunbroker, they usually have some available, but they usually go pretty high. Check gun shows also - there will usually be some there also.

Check Cabelas. I have ordered alot of primers from them lately. On their web site they say they are backordered for over a month. Most of the time I have received my primers within a couple weeks. They are around $32 per 1000. If you watch for their coupons and place a larger order with a couple of buddies it helps absorb the $20 hazardous shipping charge.
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