The barrel in your photo is from a 1938 M24, identifiable by the 'two screw' tappet cover. 1939 models had a 4 screw cover...The pictures below are of the 1939 ISDT team...The first taken at the docks in the UK, the second at the hotel in Austria where the team stayed...EOG22 has had more markings applied between the two photos...I have the original photo of the second image...Ian

email (option): ian@wright52.plus.com