Pistol lethality, and trancendent things.
Most important for a pistol round is hitting the target. You get zero to negative points for all rounds that miss.
Second most important is penetration. The important bits are at the back, and you may have to shoot through the bad guy’s arms.
Third most important is the size of the round, and the important parameter is area diameter squared divided by 4 times 3.14…. Because the target is probably movin, you don’t know exactly what bit of the body the bullet will destroy, so the advantage is to the bullet that destroys a little more.
The.380 is functionally the same as .357, .38 special, or 9mm. between 0.355 and 0.357 inches diameter. The .380 doesn’t have a lot of energy, so if your bullet expands, it won’t penetrate. If it penetrates, it must not expand. .357 magnum has more energy, so the bullet can be designed to expand a bit, and will still penetrate enough. A round that starts off at .45 inches diameter, aside from being heavier (which helps penetration) starts off with more area. An expanding .45 round (flying ash tray) can expand to larger than a 12 gauge slug.
Of course the best is not a pistol, but a shotgun. The 12 gauge, with number 1 shot puts (with 3 inch magnums) 25 each thirty caliber pellets through your enemy. That is 25 opportunities to cut a spinal chord.
Lavoisier, the discoverer of Oxygen dabbled in politics during the French Revolution, and was sent to the guillotine. His last experiment was to blink his eyes as long as possible after his head was severed. It took 16 seconds for that head to die, and another 1000 years will not produce another like it.
This was originally posted as a comment here: