A year ago I'd have easily said "go with the 20". But, after taking my (non-shooting) almost teenage brother-in-law out to the gun club and going along with another guy's recommendation to let him borrow his .410, I'm not so sure anymore that I agree that the .410's so much harder to hit things with. He broke clays as easily as I've seen other "kids" his size and age break with a 20.

Of course, since then, we put him on a 20 and he complains that he can't hit anything. Maybe some recoil sensitivity? Don't know, just starting to work on him.

Recalling the .410s of my youth, most were single-shots and ALL had fixed, full choke barrels - probably not the best alternative for shooting squirrels (or anything else, for that matter). If you can find one with choke tubes, I think I might pick it nowover a 20 for the situation you're in.