Home Forums Reloading Big Game Rifles Rule of thumb for using magnum primers?

When the load calls for it use Mag Primers.

If you are shooting in sub zero temps.

Develop loads using Mag Primers

Other than that no

Snake

I started loading in the early sixties. At the time, as far as I know, Magnum primers had not been developed, or at least I had never heard of them.

I started out using CCI, but had several misfires with them. I changed to Rem. 9 1/2, and have been using them since, in standard strength, although Magnum 9 1/2 have been developed.

The standard primers worked then, and I saw no reason to change. I have used them in Weatherby Magnums, and several standard cartridges using surplus 4831 and IMR 4350.

I still use the standard primers, and see no reason to change, although I do use Federal 215s in my .300 RUM. Haven't tried Rem. 9 1/2 in the .300 RUM, because the Federals work fine, and, again, if it works, I don't like to complicate matters.

I use mag primers on ball powders and any powder slower than IMR4320. I also always use them in any case with more capacity than a .30-06 regardless of powder type or burn rate.

The only rule of thumb I've been able to come up with for using magnum primers is when the rifle in question isn't grouping the way I think it should. Then I'll sure try magnum primers before giving up. I've found them to provide the best accuracy in .22 centerfire cases, and not just larger ones like the .220 Swift but the .22 Hornet, with certain powders.

Have also gotten excellent accuracy with standard primers in larger cases, including several belted magnums. Have always used magnum primers in the .300 Weatherby, .338 Lapua and .416 Rigby but for all I know they might work just fine with standard primers.

Have done considerable testing of primers and powders in very cold weather and never noticed any noticeable advantage to magnum primers, except once in a great while with some ball powders.

I use Fed 210M primers with Re22 and H4831 in my 280AI. 1/2" groups all day. The Re 22 loads will be for antelope this month, the H4831 will be used for late elk.

To keep things simple and prevent accidental use of the wrong primer compared to my developed loads, I use mag primers in mag cases and standard primers in the others.