The advice about using magnums with ball powders is good. Ball powders have their burning rate controlled by coatings more than grain size, so naturally the coatings are tougher to start burning, especially in the slower powders. Have found magnums to produce better accuracy with ball powders in case as small as .22-250 and .220 Swift.
As far as other cartridges and log powders, it depends. The Winchester LR primer is almost as hot as some magnums. It depends on the powder and how tightly it's packed, etc. Have tried regular primers in .416 Rigby with around 100 grains of slow burners and everything worked fine.
