My one and only .380 shooting story......
I was a mechanic for the city I live in. One day the police showed up with a car. It seems that the owner was sitting in the drive up line at a fast food place and got to fiddlin' with his brand new .380 carry gun. Yep, he shot himself.
I don't know the exact gun used, but it was described to me as one of those little pocket pistols. (On further reflection, I believe they mentioned it was an AMT Back-Up.)
Anyway, police asked me to try to find the bullet. It turns out that the bullet passed completely through the guys upper leg, through the seat, two layers of inside door panel, broke the window glass and finally stopped when it hit the outer door panel where it made a healthy dent. I found a nicely flattened FMJ inside the bottom of the door among all the broken glass.
All in all, this bullet traveled about 24" through a variety of materials including human flesh, foam rubber, plastic and auto safety glass.
I don't know about you, but I consider that pretty good penetration for an under powered .380.