[SnakeDoctor]

I think the USP frame comes in a 40 as well. Is that a better caliber than 9mm or 45?

SnakeDoc

[Recon Dad]

A few years back my son, who at the time was part of Marine Recon told me they were using .9mm and there were so many complaints with the stopping power they went back to the .45’s. They way he put it was, “you might as well throw the .9mm at them, because it was about as effective as shooting them.
The .45 is heavy and stops most anything, but it's heavy and the mags hold less rounds (probably don't need too many though)
The guy who gave us our CCW class suggested the .40 cal as almost the perfect caliber. It had stopping power and the mags held more rounds.

[Still Thinking]

I think the USP frame comes in a 40 as well. Is that a better caliber than 9mm or 45?

If it don't start with 4, don't go to war! The 40 is a downloaded version of a 10mm, originally designed for the feds to give about the same muzzle energy and velocity they had in their previous sidearms. Personally I'd take a 40 or 45 over the 9 or 10.