I have a gamo varmit hunter. It works pretty good on squrrels and birds. Crows and rabbits require head shots. I've never not shot a rabit in the head but my buddy shot a crow in the chest and it didn't die after like 5 shots and it got away. Squrrels will die with a lung shot but a head or neck shot are better. I use destroyer pellets wich leave a good sized exit hole.