As a previous poster mentioned, the spread may not be that different, to a point. I think the issue may be less what you are able to hit than what you are able to drop dead. I'm by no means a ballistics expert, but, if I remember correctly, Michael McIntosh wrote an article in Field & Stream arguing that 12's may actually be more sporting than 20's, 28's, and, especially, 410's because you kill more and wound less. As far as kick, I don't notice a significant difference between a 12 and a 20. Weight is another issue. If I'm dead wrong (pun intended) about this, please let me know. This is interesting to me.