Quote Originally Posted by Ridolpho View Post
That's pretty early. The approval date for the change was Dec. 1916 but I don't know at what serial# it occured at the 3 factories. If you peruse old threads here there may be an answer. I assume that a Mk I* bolt would not work in an unmodified Mk I receiver.

Ridolopho
Absolutely correct. Due to the longer lug length the barrel face had to be recessed to fit the MkI* spec bolt in a pre* spec receiver. There was no need to mark parts with the * marking once the change was accepted 12/16 as they were all made that way. The only reason for the marking was to let it be known that an earlier manufactured rifle was up to current spec. - BILL