I have been using a 20G and my son has been using a 12G. I'm considering buying a new O/U and I'm not sure if I should get a 12 or a 20. (The one I'm using is trouble.) Last year my son shot a grouse at maybe 15-20 yards using his 12G with a light skeet load...maybe # 8 or 9. The shot absolutely destroyed the bird with nothing much left to eat. He was using a Modified choke. I use # 6 in my 20G and have never seen that. Still I've heard of many guys using the 12G. What do you guys think?