Yeah, a pic or a close passing of a glass might help narrow the field. Concerning the gunmaking centers of Europe, I think all but France, which I think fully agreed to the CIP in 1960, for the most part had reciprocity with Britian up until the start of WWII(Sept. 1st, 1939). So unless there was an alteration, or post the commencement of WWII, seeing there is a Nitro proof I don't know why the tubes would experience another Nitro proof. I'd have to check, but East German used the "Crown" over "W" denoting constriction was used at least up until October of 1984. Post 1950, and post WWII, both parts of Germany(West used a more similar Federal Eagle) used a Bundesadler or more stylized Imperial Eagle that the Nazi period, which post 1939(April 1st, 1940- new German law) used the Reichsadler, which is more similar to the above depiction. I don't think the depection is an "Eagle"( I think WWII collectors use this term) over "N" but maybe the repair mark of "Eagle" over "J". So the period for the additional marks would narrow to say 1940 to 1945. In Germany tubes with constriction underwent an additional proof and this may account for the German choke mark, that is if there is constriction greater than 0.2mm. My question would be if the Brits would or would not accept the longarm as "in proof"??
I guess the "75" could be for chamber length, but the gauge usually accompanies it and also I'd expect to see a date stamp.
Kind Regards,
Raimey
rse
