I believe the cylinder could be reamed to .41 Mag without undo grief. However, the bore diameter is .400/.401 and the .41 mag is .410. So, it would mean a new barrel and associated smithing or bore and re-rifle the original. It wouldn't take long to use up this side of five hundred bucks.
.40/10 mm bullets are plentiful, discounting the current state of affairs, and brass is marketed by Buffalo Arms. Dies can be found and as I understand it, .41 Mag brass can be squeezed down and used.
Unless you just gotta have an honest to gosh Herters revolver, I'd say get a Blackhawk or Redhawk and be done with it.
My opinion of course and worth just what it is.
twerpy.