I remember reading dozens of magazines back in the 80s and 90s about "one shot stop" capability of the various calibers, and I remember thinking that shooting multiple rounds on target would increase those odds substantially. In other words, shoot until the threat ends. So, I carry a 9mm because I can shoot it faster and more accurately in a handgun I can carry daily. Yes, some times my wardrobe requires a .38 or .380, and with more range time I could shoot a .45 as well as I shoot a 9mm, but for now, I'm going with the 9mm, the best HP ammo that shoots well in my guns, and feeling okay about it.