I've killed geese stone dead with 1-3/8oz 2's from a 3" shell. As long as you hit em square and make "in range" shots you should have no problem with the 1's. I've noticed that many attempt to compensate for their short comings in shooting ability with a larger shell, increased velocity, bigger shot size, etc. Know your limitations and enjoy the hunt. Thats why they call it hunting, not killing.