I have been reloading for a few years but I have yet to understand the difference between magnum primers and non magnum primers weather they are pistol or rifle. Any help would be appreciated. Thanks in advance.

Mike, have you gotten an answer to the above? If not, magnum primers (rifle or pistol) have a greater "brisance" than standard. Rifle primers, small and large have the same diameter as pistol primers; however, the "walls" of the cup are taller in rifle primers; and, the cups are generally made with thicker material. For example, when the 500 S&W first was introduced, it was loaded with large pistol primers; however, the cups could not withstand the rifle cartridge pressures, so the pistol primers were replaced with large rifle primers, necessitating a "deeper" primer pocket. Starline brass marks the brass as such.
Hope that helps!
Doc with a Glock