Jerry, Lefever commonly advertised Tapered Bores. Given we don't see them that often, but the gun's conditions don't seem to reflect the need to take out .020 " [that's a lot] in the bore diameter. I think the Crossbolt Lefevers were in a period beyond black powder and corrosive priming. Even if the guns had been aftermarket altered, I would assume they would not have been altered in a tapered way as I measured.

docs.google.com/document/d/1PqK3UImDCrsOrk6O_2DsovHXvaNSzliSiwaP35Y6PMk/edit?tab=t.0