I've used magnum primers for the .30-06 case....they work fine. Further it hasn't been my experience that I needed to reduce the powder charge.....but don't assume that's true across the board...back off and work back.
While it's often assumed that magnum primers work best on ball powders....I'm not disputing this.....they also work fine on avery other powder under the sun.
If you have them.....use them.
