Okay, I almost forgot about this but in late 2012 I had an email exchange with a very well informed bloke about Austro-Hungarian proof marks. He told me (I know cos I've just had a look) that the circled "T" mark on my rifle is Austrian and was an abbreviated form of the word Tiegelgussstahl. Apparently, this denoted the use of a new high grade steel. He said it wasn't know exactly but it was thought the mark was first used during or shortly after the First World War.

Now, he also pointed out that MS hunting rifles weren't made during WW 1 and possibly not for a couple of years thereafter - so production may not have been resumed till circa 1920.

Now that's really interesting because if he's correct and the circled "T" mark appeared on MS rifles no earlier than 1920; but all non-British made rifles imported into the UK were marked as such from 1925,(which my rifle isn't) then it would strongly suggest that my rifle was probably made between about 1920 and 1925.

If anyone can further refine these dates that would be much appreciated.