Well, a 9mm is certainly better than my .380, but I’ve been a fan of a bullet that actually knocks the guy down for a long time. Hence my attitude about the .45.
Plus, when one is being pointed at you it just LOOKS scarier. :-)
No pistol bullets “actually knocks a guy down” unless he is already in a marginally stable state.
Even rifle bullets generally do not “knock a guy down”.
Bullets destroy tissue and break bones. Central nervous sytem hit, they go down; break a leg or hip bone, they go down in one step.
Hit heart and lungs.. may go down, may stay up for several seconds.
If the person shot knows they are shot, and has been programmed to go down when by television and movies, they may go down.