I watched a coon take a few shots from a 9mm with very little reaction. Darn thing just kept clinging to the side is the tree and looking at us.
My Grandpa & Uncle were coon hunters - I've seen them pump numerous 22shorts into a coon 25-30' up a tree - - - finally they'd flop out of the tree .
Yep, just gotta wait 'til they stop leaking red juice, then pretty soon gravity wins.
You're doing it wrong. Throw a thumb sized rock in the air and let them suicide on it. Bats can "see" size but not density. Usually it stuns them, doesn't kill them, but after they hit the ground you can finish 'em with your boots.
Tom