>>2496851>What do I need to know?skip anything larger than a 22.
A good pellet gun is probably your best best, anything bigger will just blow the thing apart; don't use pistols, unless you are amazing marksmen you aren't gonna get close enough for a clear shot at such a small target to hit it reliably. Look up reviews for pellet guns, they are often used pest control and have less strict rules in most places, if it can kill a New York rat it should do great for squirrel.
Some people I know use hunting bows, I have tried and it didn't work for me. I recommend a good crossbow, easier to handle for someone to used guns and a much straighter shot with more stopping power than a pellet gun.
If you really suck at aiming then try bird-shot from a from a 12 gauge shotgun with long barrel, I wouldn't recommend it though since you will be picking out metal shards from the meat