Using a small rifle primer in pistol ammunition is mostly not advisable. Below are a few important points to consider: ### Variations in Style and design 1. *Primer Composition*: Tiny rifle primers usually have a harder cup than compact pistol primers, intended to resist greater pressures related to rifle cartridges. https://knoxvccfg.blogofchange.com/31926111/using-a-tiny-rifle-primer-in-pistol-ammunition-is-usually-not-advised