Looking through some of my stuff on another subject I found that a very late Parker 28-gauge from the September 2023 G & D auction had the hang-tag and it states, "Chambered for 2 7/8 inch shell."
242103 03.jpeg
The SAAMI meeting where it was suggested that manufacturers begin marking the chamber length on their shotguns was in 1937. On Savage made A.H. Fox guns I see the chamber length markings on some 1938 guns but fully in use on 1939 guns. In my Remington pumps and autoloaders I see barrels with date codes as late as December 1940 that just have the gauge but no chamber length.
Threaded Mode