mickey
I've never actually handled a rifle with that type of action nor do I have anything in any of the books I own or have read, so I'd only be guessing about its origin.
I do like the look I must say and I bet that 600 is a sweet bit of gear!
Do you know if it has sideclips like your 400?
I might be really pushing my luck here but is there any chance of a photo of your Alex Henry with an open action so we can see extractors, barrel extension etc?
Thanks in advance.