If your rifle has a breech plug that has a design that works well with BH, you don't need to use magnum primer. My choice of primer is dictated by their length, not their heat. If your plug isn't good to use with BH, you should use the hottest primer you can find, and cross your fingers. If i knew what rifle you were going to use, i could provide a better answer.
As
sabotloader suggested, a hand turned drill to keep the flame channel open, is good. This isn't needed every shot, but if you shoot a lot, the flame channel will plug with carbon, or as
sabotloader calls it, 'the new crud ring'.