I am able to find Magnum rifle primers, but not standard rifle primers. Is there a formula to back off the powder and work up the load using mag primers?

Is this do-able or is the mix just wrong for the powder?
Thanks.

I can't answer from the minimal info you've given, but the General Rule still applies: when you change ANYTHING in a load, back off and retest.

Whenever I find a Pet Load, I create what I call a Benchmark Load (BM), which uses the exact same components but with the powder charge reduced by 5%. I record everything possible about the BM.

When I change any components (new can of powder, different batch of primers, new box of bullets, new brass...) the first load I assemble duplicates the BM.

The new load will test the same, cooler or hotter than the BM. If it's the same, I go back to the Pet Load immediately. If it's cooler, I can go back to the Pet Load and work up slightly. No problem.

The real value of all this is when the new load tests hotter than the BM. Then I know that the Pet Load will also be too hot. I can work up from the BM safely.

And I learned it without ever firing a dangerous load.

So, before you switch primers, back off the powder charge of your favorite load by 5% and shoot that load.. Then retest that same reduced load with magnum primers and see what happens.

Good advice.

If you shoot out at the Rio Salado Sportsmans Club range - I'll see you there! :D

I agree with backing off, and starting over. Safety first. My question is more in the direction of will it just not work well. Will it burn too fast, to hot, to be effective or accurate with powders that don't call for them.

Any experience with changing from standard to magnum primers. Did the accuracy drop off? Did it show pressure signs without achieving expected velocity?

Thanks for the input.

Ps. kdub - I do shoot at Rio Salado almost every weekend.