I've said it before, others have said it here, the choice of gun and the ability to use it well matter more than the caliber.
Discussing 9mm vs. .45acp cartridge performance alone is simply a matter of specs, and does NOT equate directly to field performance. Sure, there is a connection, but the 9mm does not do this, or that, better or worse simply because it is the newest, hottest +p+ whomper stomper 9mm there is.
IF you are going to hold one up above the other, 9mm vs. .45, based on the cartridge
alone, then level the rest of the playing field, or the discussion is pointless.
Here's your defensive weapon, a single shot T/C Contender with a 6" barrel (for convenience
). You have two barrels, one in 9mm Luger, one in .45ACP. Which one do you choose??? why?