Under the fore end one barrel has what I assume to be a serial #15519. The other barrel has a Crown/NI. The serial#15519 is also on the butt plate and color case harden frame. There are some other stampings but I can't make them out. The only name I find is Suhl on the base of the rib between the barrels. There is a monogram above the Suhl stamping I do not have a gauge to measure either barrel, they appear to be the same size. I do have a 45-70 that looks about the same size. The veteran took it to a gunsmith who told him it was a 460.