RE: 10 ga vs. 12 ga.
I have never shot a bird with a 10ga...but sat by a buddy while he did. was that impressive.
He's a goose hunter, so he just switched chokes and hunted gobblers with the same gun. It is a Browning semi-auto. He shot a big bird at 55yds, and there was never a flop.
I don't think it's necessary, but a 10ga is highly effective! LOL