Rob, I simply had not found the time yet and need to admit that despite I'm not that old I do forget to take out the rifle and the caliper when I'm back home in the evening. But will do it!
This particular rifle was purchased at Poulin Antiques in an auction, the only good thing is that they didn't knew what I knew on this rifle and had not described what it was (well, they did describe it as a sniper - but they didn't give the name of the sniper converter, the provenance of the Pattern Room and the fact that it is the only known survivor).