As Erich states, proper bullet placement is key. If you want to carry a .380 as a primary weapon, I don't believe that you can reliably stop a full sized man with any certainty. As a secondary weapon, it could be OK at very short range.

I shot my new (never fired) North American Arms .380 Guardian the other day at a dark indoor range. At 7 yards, I kept all of the rounds in a vital zone, but the pattern was poor. The sights are non-existent on this pistol and with a 10-12 + pound trigger pull, these groups were nothing special.

I wouldn't trust this caliber as my only weapon. A "j" frame S&W is much better even though it is not an easy weapon to shoot with an aluminum frame.