Was exported to the UK as a .455. It was converted to .45acp/auto rim at some point.
Something doesn't seem right ~ the British Purchasing Commission objected to the third lock at the yoke and specifically stated that it be eliminated. So far as I know, no .455s were Triple Lock. All known Triple Locks that I know of are .44 Specials.
I believe there was one .455 Triple Lock made up, but it also had the full ejector rod shroud. Both of these features were to be eliminated on contrtact guns.