This may be a really stupid question, but I have to ask it. I talked with a guy at the range yesterday that said "don't be afraid to try magnum primers even if your shell doesn't call for them (i.e. use Rem 9.5M instead of 9.5)." He said in one particular rifle he has, they dropped his group size in half. In another rifle, they didn't affect it much. Is this a smart thing to do? Obviously, you would have to start with a reduced load and work up, but will this help with completing ignition or is this just an accident waiting to happen? The rifle we were talking about was a 22-250.

Jethro:

I don't have any reservations as to using a "magnum" primer with any cartridge. The purpose of the magnum primers is to deliver a hotter flash to ignite larger powder charges. My Speer reloading manual also recommends using magnum primers when ball powders such as W760 are used in non-magnum cases.

You hit the nail on the head when you said that you should start low and work up, just like with any change in components.

Best of luck, 8point

Ditto what 8point and the guy you met at the range said. Heck, I use Small Rifle Magnums in some 223 loads.

Some loads respond well to changes in primers, if the rifle is accurate enough to show it, as most 22-250's are. Treat your load workup with the magnum primers the same as you would a workup with regular primers - you don't have to reduce the starting load or anything. Now, if you have worked up to whatever you consider MAX with standard primers, and you want to change to magnums, you should reduce by 5% or so, and work from there.

A "magnum" primer is not necessarily hotter than all standard primers. W-W's WLR primer, for instance, is probably hotter than an R9-1/2M, at least based on various test results I've seen.

If you have access to the latest (February, I think) copy of 'Handloader', Barsness has a good article about primers in there.

R-WEST

I've used CCI-250 magnum primers in my 22-250 for 20 years. 42 grains of H-380 under 50 grain bullets. No problems here. I use magnum primers for everything. They help keep the velocity changes from cold to hot to a minimum.

The purpose of a magnum primer is to provide a hotter flame and a longer duration, to ignite some of the powders such as Ball Powders, which are harder to ignite than some of the others.

You will never hurt anything by trying them in a load, so long as you reduce the powder charge appropriately when doing so.

Once in a while, you can find a load that benefits from the change. More often than not though, your load will suffer somewhere, if you use an inappropriate primer.

The best policy is to use the primer type that is recommended for the particular load you are working with. The suggestion to use a mag primer for everything is foolhardy at best. If this was the thing to do, then they would be so recommended in the load books and the manufacturers would only make one kind if primer.
It simply doesn't work that way.

In the case of your 22-250, I've shot litterly thousands of rounds of that ammo. My personal load is a real screamer. 3810 FPS. Never have I ever used a Mag primer, and have used the load for over 30 years. Just isn't necessary, or needed.

Regards DLM