Muzzle loaders for wildfowling, particularly over the dykes in drained marshes were made in 60" and possibly longer.
That is interesting. Most were cylinder board out to the muzzle. A 60" barrel will kill cleanly every bit of 32" farther than a 28" gun. The concept of choke constriction was really quite a turning point in shotgunning. And, I hope that comment doesn't start a maelstrom of criticism of shooting at "long distance" birds.
Wasn't the idea to allow more room to burn very large charges of black?
SRH