My dad, when he was alive, used to poach deer with a .22LR to put food on our table. So, it isn’t recommended and probably not legal for anything other than small game, but in a SHTF situation, it will do.
I owned a Missouri-made .50 cal air rifle for a few years, then sold it.
It took a Scuba tank to fill it, giving four shots of .495 round ball.
It would take a deer north-south or east-west.