Been the subject of quite a few threads lately - finesse the load and ignore that other things are more important. We can recommend .380 loads until the cows come home but the reality is that shot placement, reliable operation, and affordability/accessibility are much more important. So much so they control actual results in the field - not a gel test conducted under academic conditions.
The proof of the pudding that .380 ammo is a moving target of potential performance is right out there on the market. Older loads were designed for older European guns with barrels up to 4", the new loads are built for the substantially shorter 3" pocket pistol market. If the change in barrel lenght can move the expansion window 4-6" in tests - which Shootingthebull seems to have demonstrated in his findings - then good luck dealing with variations of 40 feet in range, what seasonal clothing may be involved, and what the strike zone is on that individual.
Shot placement, barrier performance, and how the individual reacts to the wound vary considerably. It's been noted b a lot of battlefield casualty studies that a small wound in the upper arm from small arms fire might disable a soldier completely, vs multiple hits from .50BMG being unable to stop a soldier who goes on to win the fight against larger numerical odds.
It will make little difference what bullet you pick if the opponent is hyped up on crack and predisposed to injuring someone who just hurt them. .380 is then considered after action to be inadequate - as is 9mm, .40S&W, and even .44. When they won't go down, no gun is big enough and there's a rush to move to a larger platform. The reality is shot placement and how it's assimilated has a much larger affect than what Bullet of the Month is currently "best." Its actually dangerous to focus too closely on the market offerings - it takes away focus on training and mindset. Carrying "Critical Devastator Zombie Slayers" props up a fantasy notion of invincibility that will vanish like mist in the face of a thug who didn't drop on the first shot.
Better to pick an affordable round you can find on the shelf and will shoot in practice rather than hunting down niche rounds celebrated as the Death Dealer on the internet. I find that is exactly the problem I have buying ammo - all the hot players are an empty spot on the shelf and $5 a box higher. I grab the middle of the pack performer, stick to one brand across the board, and find it there every time I shop. That provides consistency in supply until I choose to dedicate a 1,000 round internet purchase of it. What good are the legendary bullets of the FBI, HRT, SEALS, or whoever if you can't get them cheaply enough and practice?
Inflating your ammo budget 15 to 25% just to get them means shooting 15 to 25% less ammo for some. How do you get better at shot placement by shooting and practicing less? Never have seen that to work out well.
It's been said of expert knife users - they can do very well with a 2" Case Trapper when their inexperienced opponent is even armed with a Kabar. SKILL is far more important than the incremental and arguable improvement in knock down power - which is it's own area of controversy that's been around for decades. Face it, handguns aren't known for having "knock down power." That takes large caliber rifles to accomplish, and the results aren't guaranteed. See the above on .50BMG.
Looking for the best lethal bullet is chasing a rabbit. Buy quality and practice, the real goal and best tool you have are your skills.