FOR ME - - -> I Use CCI450,CCI250,and Fed215 for most everything. This way if I happen to use a hard to ignite powder,I got the primers already seated in the brass. Check the reloading manuals. There are a bunch of loads that reccomend mag primers. There are no loads that say you can't use them but common sense prevails.
My rule is . . . if I switch from regular to mag primer,I drop back one full grain of powder. ---- SAWMAN