Larry we have some members in the L.C. Smith organization that do have chamber lengths stamped into the barrels water table from the factory that were not common. As Brother Drew posted one 12 ga. that has 2 5/8" chambers. I know of one member that has an early pre-1913 16 gauge with 3" chambers stamped as so.
L.C. Smiths 10 gauges, 2 7/8" chambers, 12 gauge from the beginning, 2 3/4" and with the coming of the Longrange and Waterfowl guns, 3" chambers, but not all, 16 gauge, 2 9/16", 20 gauge 2 1/2" 28 gauge (1) 2 1/2", .410 beginning 2 1/2".
I don't know exactly when the .410 changed to 3", but the 20 gauge was in the early to mid thirties, 16 gauge was late 30's early 1940.
Any thing different than these dimensions were stamped on the barrels water table.
When both the 20 gauge and 16 gauge were first lengthened, the factory stamped Chambered 2 3/4" in a straight line on the water table. After a period of time I believe they left it off.
