The dictum to "always" use magnum primers with ball powders is baloney.
Just because a cartridge says "magnum" in it's name doesn't mean it needs a magnum primer and even if it's not named magnum doesn't mean it might not do better with a magnum primer. Furthermore, loading manuals list one type of primer ONLY because they aren't going to use a bunch of different primers in load testing and some loading companies have economic affiliations with certain brands of primers. A primer just lights the fire and has relatively little contribution to the pressure a cartridge generates.
One example in my case is the use of Federal 210M (large rifle match) in a 7mm Remington Magnum. In my 44 Magnum I've used large pistol, large pistol magnum AND large rifle magnum primers though in the latter I had to reduce my H110/Win. 296 load by 1 or 2 grains. The key to ANY safe reloading is to start low, work up in sensible steps, consult reloading manuals and know and heed pressure signs in the firearm you're shooting. If you do that, you can switch primers with no problem.