I load my .357 mag rounds with a magnum primer even though it doesn't call for one. I started with Federal primers and switched to Tula when they ran out. It works just as well for me. My load is 10.2 grains of AA7 with a Montana Gold 158 grain JHP bullet.
The powder manufacture show a NOS JHP bullet using a Winchester magnum primer 9.5 to 10.5 grains of AA7 and Speer shows 10.5 to 11.7 of AA7 with a 158 grain JHP using a standard primer. You will notice you do use less powder with the magnum primer. I like the load with the magnum primer better so that is what I use. It burns pretty clean and is pretty accurate too. I shoot from a 4" barrel pistol. You will need to work up your load for your pistol to make certain it works for you.