I have a New Englander but I have never tried to shoot steel shot through it.
Modern shotguns don't need special chrome lined barrels to shoot steel but shotshells loaded with steel shot use special plastic shot protector wads that prevent the steel shot from touching the barrel. Think of these wads as sabots for shot. The biggest issue is the choke, steel shot doesn't compress as it goes through the choke and can damage chokes in thin barrels, especially if it is a full choke.
If your barrel has a cylinder choke and you use a modern shot protector wad meant for steel and you make sure that the entire load of shot is inside the shot cup, I bet you won't damage the barrel but one piece plastic wads are notorious for plastic fouling in muzzle loaders.
Modern shotguns don't need special chrome lined barrels to shoot steel but shotshells loaded with steel shot use special plastic shot protector wads that prevent the steel shot from touching the barrel. Think of these wads as sabots for shot. The biggest issue is the choke, steel shot doesn't compress as it goes through the choke and can damage chokes in thin barrels, especially if it is a full choke.
If your barrel has a cylinder choke and you use a modern shot protector wad meant for steel and you make sure that the entire load of shot is inside the shot cup, I bet you won't damage the barrel but one piece plastic wads are notorious for plastic fouling in muzzle loaders.