Reading thru this thread I'm not clear that the 2XX mark is indicitive of bore diameter. My view/opinion is that the proof house had a cartridge number requirement for any particular drilling/DR that may have passed thru their doors. (This mark/number designator would of course be somewhat time period dependent) In other words the 2xx number might correspond to 7mm Rimmed (7x57R) Also and it needs to be noted here that the "181" mark on drillings and and ocassionally seen on DR tubes equates to .30-.30 Winchester not 303 British. (This from German guns that I have owned, handled and inspected) I currently own a Sauer Drilling with "181" on the barrel and it is most definitly chambered for .30-.30 In regards to the three digit caliber marks, thus far I have only seen the '181' mark but have been looking for others....so the 2xx mark is intriging to me. Does any one else have any marks similar to above stamped on barrel(s) for known calibers/cartridges? I am not discounting Ellenbr and 2Pipers work and thoughts on the barrel marks but until I see more evidence that it all pencils out (bore/gage), for a number of other cartridges/calibers I remain....curious. Jeff
