I started duck hunting and learned that most shotguns have almost the same vecoicty(20,16,12,or 10). Its my opinion that the only differince is the number of pellets, and the pattern, aka, choke. Me personaly, if you stayed within 30 to 35 yards you would be fine with a 20 gauge full choke. Modifide you might want to stay in the 25 to 30 yard range.