I use standard CCI or Winchester small rifle primers for all of my 223 loads.
I've never experienced any better results using a magnum primer in a small caliber,and would only use them if a load called for them exclusively.
Ok thanks for all the info . My Lee master loader instructions say do not use magnum primers. So when all else fails , following the instructions would probably be the safest option. I am going to load a few and try them as I go . Thanks again