Not to hijack the thread, I have a T&S Nimrod drilling, 16x16 over 8x57R built in 1939. The chambers are 70mm but the gun is not marked as such. My gunsmith and Dieter Appel both inspected the gun and feel the chambers are original.
The question is, when would 70mm chambers have become standard for 16ga? I know that when 65mm was standard any gun without a chamber length marking was assumed to be a 65mm. Only if the chamber length was 70mm would it need to be stamped 70mm. But my gun being such a late gun, 1939, 70mmm was the "standard" 16ga size at the time. When 70mm became the 16 ga standard would a gun still need to be marked 70mm?
