David:
I am rather confused - and intrigued - by your post. Are you saying that you have a Mark I Martini-Henry rifle with a
solid (i.e. un-split) steel pin retained by a keeper screw? As I understand it, that would be an odd duck indeed. In any event, your impression that an earlier steel axis pin retained by a keeper screw was replaced later in the development process by a split bronze axis pin (without keeper screw) reflects some definite misunderstanding, I'm afraid ....
it was a
solid bronze pin retained by a keeper screw which effectively came first. The directive to replace the bronze pin with a
split steel axis pin (thus eliminating the need for a keeper screw) was not made until well into 1874, and that modification was officially adopted with publication of the final "Approved Pattern" Mark I specifications in the List of Changes 16 July 1874. Indeed, all "Approved Pattern" Mark I rifles (including earlier pattern rifles which got upgraded to that pattern in accordance with the War Department directive) - as well as all Mark II, III and IV rifles - should have a
split steel axis pin -
According to David Edgecombe (
"Defending the Dominion: Canadian military Rifles, 1855-1955") all known Canadian-purchase Mark I rifles are the "second pattern", none of which got returned for upgrading to the Approved Pattern, and thus should have the solid bronze axis pin - as well as the earlier large cocking indicator -
(All known Canadian Mark I rifles show no evidence of removal of the very early action safety, which had in fact already been eliminated from production before the Canadian rifle order was placed in December of 1873.)
As a side note - if there
was any sort of corrosion issue involved in the variation of the axis pin, it strikes me that it would actually have been attributable to galvanic reaction between dissimilar metals - i.e. the original bronze pin and the steel receiver - rather than from contact between two steel parts. After all, the other parts of the Martini-Henry action (and most action types, for that matter) which contact each other are all made of steel ....)
I do gather from some oblique comments in certain references that at least some of the "first pattern" - which was actually not even called the Mark I in official documentation but has come to be considered to be the earliest pattern of Mark I rifle - may have had a steel pin, but I am not clear on that nor on the configuration of the pin (i.e. split or solid.) In any event, the Second (Final) Trials Report, presented 8 February 1871, indicates that the block axis pin was "to be made of gun metal
[i.e. bronze], to be a simple pin, kept in position by an ellipse or keeper screw". Apparently that pattern of pin was supposed to be retrofitted to the relatively few rifles produced earlier without it.
You describe your rifle as a "Canadian Mark I in its original configuration", but if it has an un-split steel axis pin retained by a keeper screw, I would speculate that the original bronze pin has in fact been replaced at some time with a steel one machined to the same dimensions. Can you post pictures of your receiver and axis pin?
Also, does your rifle have Canadian markings ("DC in diamond" or otherwise) - Canadian-
marked rifles being relatively uncommon, as I understand it - or is your identification of it as Canadian based on other factors?