Do not try to judge handgun bullet performance on any small animal too stupid to know you killed it several times over.
Possums, and from what little I know about them, armadillo's, have only a rudimentary central nervous system and a tiny brain just barely big enough to do what they do.
Dig holes, eat anything, breed, and crap.
I have shot possums to doll-rags with a .22 autoloader until I ran out of ammo.
Then come back an hour later and find they got up and walked off.
If you don't shoot them in the head and hit the tiny brain, or blow them apart with a rifle or shotgun, they ain't dead until they leak to death somewhere else.
rc