Perhaps the best way to ask this is how to get the most out of a 9mm.

I don't get into a lot of specifics, but I have no doubt that a good 9mm SD load will fill the bill for self defense. Most of the detractions of 9mm are based on military use, which mandates FMJ ammo.

Take a look at these:

Inceptor Preferred Defense | Polycase Ammunition

The bullets are available for reloading in both the composite and solid copper. They don't expand, but the shape produces a very large wound channel with excellent penetration. If I were determined to use a .380 for SD, I would be looking really hard at these bullets.

And don't forget that accuracy trumps caliber every time.