Some of the early Lefever were bored to what we consider over bored size. I had one that was a perfect .750 bore with walls that were .045 at their thinnest point. Heck of a heavy water fowl gun with chokes that were .045 or .050 as I recall. Have a Baker with .7550 bores that are .050 thick and comes in at 9 plus pounds.
Never got to use the Lefever on one ducks or geese. I did shoot one mallard with bismuth shot with the Baker at a range that still impresses my son for a long shot. I wish that we could get a one day a year lead shot season with classic double guns or pay a yearly special lead use permit to shoot classic doubles.