Re: Magnum primers in place of standard?
I have a friend who has reloaded for 40 years, and he uses Magnum primers in all his reloading. He said he ran a test to see what the difference was when loading w/a standard primer vs. a magnum primer. He found that with a magnum primer it took about a grain of powder less to achieve the same velocities with lower SD and less ES - FWIW.
Be careful as always (work up), as I have not tested this out.
And if you want to part with some of those primers as well LMK LOL.