The 9MM (as we know it, the 9x19) was designed SPECIFICALLY for increasing velocity thereby increasing the terminal effectiveness and accuracy of the P-08 Luger. Fact.
Kenyon and Walter each have written very good reference books with much factual research and documentation included.

Even the FBI issues G17's to agents deployed overseas. Fact.

England moved to a smaller caliber revolver from the .455 to increase velocity and effectiveness. Then, to the 9MM Hi-Power. Fact.

More 9MM handguns have been built for military contract and duty than Colt's ever built .45ACP's for military contract and duty. Fact.


I've never stated the 9MM is exclusively superior, nor have I disparaged the .45ACP. In current defensive loadings, which means everything to the current CCW permit holder, it's a damn fine line between the effectiveness of service caliber loadings.
They are all that close in performance.
Fact.
And it is well documented.

We have to consider ourselves quite fortunate to have all the choices we have at our disposal. Caliber or platform, the most important thing in being successful is mindset.