I just picked this Alex Henry up and thought I would share some pictures. It was sold in May of 1882 in a small batch according to the Alex Henry book by Donald Dallas published in England. It is not one of the military contract rifles as they were not listed in Henry's books. Also it has a right hand cranked lock that is front bolted or safety. I cast the chamber an it is a #2 musket, not the normal Henry long or 577-450. the bore is excellent so we will have to see how it shoots. it has a 9 groove barrel instead of the usual 7 groove of the standard military models. Possibly a sealing rifle as it has some pitting on the out side like being exposed to salt air.

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Don't know where my first reply went , but here goes again. Yes I plan on making molds from it. I think i can borrow a pistol grip cranked lock to copy, so will be able to make a proper gentleman's sporting or target rifle. I started out building muzzleloaders in 1971, so having a lock just seems proper somehow, right?

I think I know of the location of that cranked lock for you to copy.  Sounds like a good idea.  See you both in Tulsa.   
Bruce

rodney,
what would you estimate the transition anlge beteen the chamber and the bore to be?
keep safe,
bruce.

Reply to Bruce molds . I looked at the chamber cast and there is no lead from the end of chamber into the rifling on one side and a very slight angle wear on the other side. The end of the chamber,  radius's  in not square or 45 degrees like others I have seen, hope that answers you question.

Forget about the usual modern 45 degree transition on such rifles, usually there will be a very gentle transition from the case mouth to the rifling, either a bit oversize or using a bore-diameter bullet.
The Gibbs MBL rifle (Field action) I have is an example of the latter:  The chamber will only accept a bore-diameter bullet - which BTW is actually .461.  And yes, that bullet will slide from chamber to muzzle through the (knackered, unfortunately) Metford barrel with next to no resistance.