If your starting low (5-7% or more below MAX load) and work up, it doesn't matter much which primer you use, regular or magnum. I like to use .3 grain increments, until I get to cases that use over 60 grains, then I go .5 grain increments. Just use good techniques and watch for pressure signs and/or use a Chrono. On the other hand if you already developed a load with regular primers, and now want to switch to magnums, reduce your charge 2-3 grains and work back up.
