Personally, I carry a Smith & Wesson manufactured Walther PPK/S loaded with Hornady American Gunner XTPs.

Based on what I've seen, the XTP bullet design is the best all around performer when it comes to JHPs in .380 ACP due to its ability to consistently expand while penetrating 12" in Ballistics Gel. Say what you will about Ballistics Gel tests, but the fact that XTPs can reach 12" with uniform expansion while other bullets will either expand but only reach around 8" or fail to expand and overpenetrate still says something in regards to its overall performance.

I know that some folks insist that FMJ is the only way to go when it comes to .380 ACP, but I cannot in good conscience use bullets which are all but guaranteed to cause collateral damage of some kind due to overpenetration. Sure, maybe the .380 ACP will dump enough energy into the target that the bullet will deal minimal damage to anyone/anything behind it, but that's not a chance that I'm willing to take.

Personally, I feel that the .380 ACP is underrated/underestimated as a self-defense cartridge. It's roughly equivalent to standard pressure .38 Special, (which many folks carry) yet for some reason it is rated much lower.
Furthermore, many folks are practically in love with the 9mm Luger cartridge, often touting it as the ideal self-defense cartridge, yet if you compare two similar pistols chambered in .380 ACP and 9mm Luger side-by-side like the SIG P238 and P938, the actual amount of damage (penetration depth, wound channel, etc) dealt to just about everything from Ballistics Gel to animals is extremely similar, in spite of what the large differences in numerical figures like velocity, foot-pounds, and pressure may suggest, ergo while the 9mm Luger is undoubtedly more powerful than .380 ACP, out of short barrels it seems to only beget a marginal improvement, yet folks still ask, "Why carry a .380 when you can carry a nine?"