Recoil Rob:
I wouldn't say you are hijacking the thread at all but providing pertient info as well as raising more interesting questions and that is the purpose of this board. I'm just stating what is in "The Standard Directory of Proof Marks" by Gerhard Wirnsberger in 1975 which I believe is based on Baron Engelhardt's research up to 1955, it states that after 1912, any barrel with 70mm chambers had to have the number "70" on the flats, but I guess there are exceptions. I would guess that the standardization of the chambers was some time in the last 1920's or early 30's as the Ithaca Gun Co. offers a 16 bore in 2 3/4" after August 1924 but in 1932 still lists the 16 bore as 2 9/16ths inch. One another note, does your drilling have the stairstep watertable?
Kind Regards,
Raimey
rse
