>>27699591Again - depends where you are at. UK, for example, has a problem with American Grey Squirrels (check.
northernredsquirrels.org.uk), so it's always ok to shoot greys dead.
I wouldn't do it with an air revolver, since those put out 6 foot pounds or less, and squirrels are tough buggers, and you will need more than 6fpe for a clean kill.
I see no ethical problem with carrying an air pistol (i have a Baikal mp654k in my car for shits and giggles), but like I said - I'd not shoot the squirrels unless I was confident it would be a clean kill, so I'd stick to air rifles for that.
A 16J (12 foot pound) springer in .22 caliber will do the job, so long as you can reliably brain the critter and are no further than 35-40 yards (the closer, the better ofc).