Thanks to all for your kind comments. These old revolvers are treasures to be preserved for now and for the next generation. I do intend to get a letter on this one, but just haven't done it yet. I think the commercial production of the .455 Mk II was extremely unusual, and I would like to know more about the origin of this particular piece.

Yes, the various caretakers over the years have been careful with this one. It is pristine internally also. The bore and all chambers are as new. Its action is smooth as silk. The revolver is completely un-molested and will certainly stay that way in my hands.

Does anyone have any information about the commercial production of these? This one certainly didn't go to England, because under British law it couldn't have come out of customs without being proofed. Did Canada have mandatory proof also? I'm thinking so, but can't say that with authority. Did S&W produce any .455 revolvers for U.S. customers? Seems unlikely. You can see this piece is something of a brain tease to me. Maybe someone here can help sort it out.