Bob Brister discusses the Nilo Lethality Computer Model and waterfowl loads starting on p.184 of
Shotgunning: The Art and the Science. The Winchester SuperX XX 3" 1 7/8oz. lead 4s had a rating of 70% clean kills at 60 yds with a full choke for
perfectly centered birds. That's a very different load from those used prior to introduction of the Super-X 3" in 1922.
A buddy once killed a sage grouse at about 50 yds near Pinedale, WY with a single pellet in the head. He grew up shooting pheasants in SW KS and was a tremendous wing shot, but thereafter he let go at any bird within 60 yds
