I just thought to measure the diameter of my various 9mm bullets at the base with my digital caliper. The results were a little surprising: MG 124gr CMJ 0.354" JHP 0.3535" PD 124gr FMJ 0.354" - 0.3545" JHP 0.3545" X-Treme 147gr 0.355" BBI 130gr 0.3555" - 0.357" Speer 147gr GDHP 0.354" - 0.355" Random 9mm 115gr bullet I pulled from what I assume was factory round picked up at the range (may have been PMC) some time ago was 0.3535". The BBI's generally won't gauge in my Dillon 9mm