If you're worried about over penetration with a handgun use a good name brand JHP and instead of testing ammo on poor innocent fruit, be a responsible gun owner and train for target aquisition.
As stated above, in an actual self defense shooting there's a lot of stray rounds, so one of the most important things you can do is get a good target identification which also means knowing what's behind your target. If it's a wall with your kids' bedroom on the other side, you might want to re-consider taking the shot, no matter what kind of ammo you have.
If you're worried about over penetration with a rifle, use a handgun.
A hit with a .45 ACP beats a hit with a .22 LR everytime. A hit with a .22 LR beats a miss with a .50 BMG everytime.