Try Bismuth and you may never use steel again. If flat out puts them down. I use 2 3/4" #4 and #5 for ducks and geese and it knocks them out of the air. I grew up in Baltimore hunting geese and ducks on the Eastern Shore and Bismuth reminds me of when we could hit them with lead.
Bismuth is the way to go. Do not go with steel or tungstan! I loaded some bismuth up for a buddy of mine to shoot in his old doubles. If you buy off the shelf stuff watch out not to get shells that are too strong for the gun to handle. My buddys guns were old so I basically loaded up light trap loads with bismuth 4 shot.