Using rifle primers indescrimenately in pistol loads can be problematic. They are much hotter than psitol primers, even hotter than magnum pistol primers. SO unless you are reowrking your loads, not a good idea. The other issue is the rifle primers are "harder", so will not fire in some striker fired guns or guns that have tuned triggers. The final issue is the magnum primer will disguise pressure issues as they will not flow like a pistol primer. This could mean a KB instead of an observed high pressure event. You will not find ANY vetted, printed data calling for rifle primers in handgun loads but for the 454cas & maybe the newer 480 & 500 mags.