Three of us went several years ago for doves only. All with 20 ga. I had a Beretta O/U with 30 " bbls and a Pachmeyer pad. Others took a M21 and a Browning A5. All performed flawlessly. Nearly 1,000 shells per day per man. The Fiocci shells we used were good, and they were clean, so less concern with gumming things up. I would stay away from 12 bore. 20 or 28 ga. is plenty.