Why not use a bigger shot size?

[Dustin07]

softball.. use heaviest bat you can without it slowing down your batspeed.
duck hunting... use smallest shot you can without it leaving you with cripples you cant retrieve.

That's my mentality. I've killed a lot of birds with BB, but throwing huge pellets at smaller ducks tends to just destroy the meat, and definitely eliminates a trophy mount.

[gwpsage]

I had the same experience having a 3 1/2 inch BB in the chamber I killed 3 teal with one passing shot.  I think it all depends on choke and distance of the shot.  I use #2's mainly for ducks and hardly ever have to chase down cripples.