I haven't had access to the Parker Bros. records to search for 3-inch 16-gauges, but I suspect they exist. In that Parker Bros. by and large didn't mark the chamber length on their guns, only a letter or the original hang-tag can verify a non-standard chamber. There was a series of reports in the sporting press back in the day of A.W. DuBray making the rounds in the southeast doing his hunting using a 16-gauge with 2 7/8 inch shells.
The SAAMI meeting where it was "suggested" that our manufacturers start marking the chamber length on their guns was in 1937. None of my Remington pumps or autoloaders from the 1930s are marked with the chamber length. I don't have one from 1939 or 1940, but my 1941 Remington Sportsman is marked while my guns from 1936 and 1938 are not marked.
The late Remington Parkers were marked on the barrel lug with grade, gauge and chamber length --
Where Parker Bros. put the serial number --
Savage Arms Corp. started marking some of their Fox guns in 1938 and most all in 1939 onward --
I did search the A.H. Fox Gun Co. graded gun production records and found 8 or 9 3-inch 16-gauges and one ordered for 2 7/8 inch shells.
