This guy has endless supply of Conehammer

[alvin]

From pictures posted, I only see two seam lines. One is at the middle of the barrel (1), and another is near the muzzle (3). I would think the gunsmith cut 2/3 of the old barrel off, brazing welded (using silver or copper) a section of new barrel with relatively better bore to it. The seam line near muzzle (3) might came with the brazed-on new barrel -- it had also been reworked on the front sight (4) before marrying with this gun.

Please also note the text on the brazed-on barrel (2). It's not readable. Some British dealers put their names on the gun barrel saying who sold it. The replaced barrel might came from a captured British gun during the Boer War. Of course, without see the exact text, that's only an estimation. The text could also be a recent U.S. importer stamp.