I have had good success on geese with my Remington 870 using 2 3/4" Federal T shot and 2 3/4" Remington BB's. My 11-87 killed a couple geese the other day with some #2, 3" Hevi-shot. I haven't found a duck load that seems reliable, although it might be me. The mallards are tougher to keep up with on the swing. I've been using # 4's for the ducks.