Well, the shotgun gods smiled on me once more. Several years ago Numrich made (or had made for them) reproduction 1897 trenchgun barrels for conversions. One popped up online and I snagged it. Hopefully the original full choke bore isn't too badly pitted that I can save it, so I have both front ends to swap when I'm done. It's gonna be another long project(s). I'll post pics when when everything gets here, then take my time learning and getting by bearings cleaning them up before converting.