If you substitute magnum for standard primers (or vice versa) you are essentially on your own, as the published load data will no longer be valid - unless you happen to find some that lists those exact components.
Switching ANY component can raise, lower or have little effect on the pressures generated, and there's no way to predict which way it will go. I developed a handy and efficient way to determine the effect you'll have, but it only works if you already have a safe load BEFORE you switch components. Read it here:
http://www.reloadingroom.com/index_files/95S.htm
If you don't have an established load for YOUR gun, the method doesn't work; you are developing load data from scratch.