It is not true that chamber lengths were not marked until Marlin bought Hunter Arms in 1945. I have a 1933 16ga field that is marked 2 3/4" on the barrel flats, and a 1936 .410 that is also marked 3" on the flats.
After working on a large number of customer and personal L.C. Smiths over the years, I have NEVER viewed one with chamber markings other than the .410, yes, the 3" long range yes, the Marlin built guns, yes........other Hunter manufactured guns, no.........it is most likely your '33 16 has replacement barrels...?......I have several 16's from the '30's and NONE have chamber markings......same with my 12's and 20's etc. from the non-Marlin era........Brophy and Houchins also note no chamber markings as standard......
Drew and JDW and others will be along shortly and give you the update and pictures/data on how many L.C. Smith barrel flats were marked with FACTORY chamber dimensions prior to 1940.....
