i use magnum primers almost exclusively. just start somewhere in the middle and work up. just like any other round. dont ever exceed max or minimum charge weights. magnum primers work great in the cold on difficult to ignite powders. they really dont add much if anything to the pressure curve.
to get true velocity info you need a chronograph. what the loading manuals say is just guess work as they take averages based off one test gun. your individual barrel type of rifling case used exact bullet temperature barrel length gas system if any all play a role in velocity
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
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