I don't know Jim, I've seen crows shot with them that were still alive when recovered and armadillos just scurry off to it's hole like nothing happened. My Jack Russell caught one before it disappeared so we did an autopsy and found the bullet had penetrated the shell and caused a large superficial wound in the flesh, didn't even break the shoulder bone. IMO, the 17 is too destructive for squirrels if one intends on eating them but not enough for anything else. I'll stick with the .22 LR and if that don't do the job I have a .22 Magnum. Would'nt mind giving the 5mm a try though.