Re: Magnum primers as opposed to normal large primers
Follow richards guidance. It's good!
My experience says that in '06 sized cases and most probably smaller, CCi 200s have always shown greater accuracy that cci 250s, in my rifles.
In large case magnums, I've found, as revealed by a noted rifle smith, that Federal 215s are a bit hotter than Federal 215 GMs.
Again follow the advice given.
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!