1907 records show L.C. Smith 12 ga. to be .728. In 1936 they show them to be .729 both right past the forcing cones.
Later I see tolerances for .732 +.000-.002.
Most have .729-.732.
I do have a 1913 Specialty Gr. with both bores at .723 and .014 choke in right barrel and .010 in left barrel. Has a HOT trigger and wonder if it was set up for a lefty.
Only one other with small bores and that is a 1899 back action hammer gun with .724 bores and .040 choke in both barrels.
16 ga. from inception, 1895-96 were .650 bores and sometime in the 1930's were changed to .662. Chambers were 2 9/16" until late 1930's early 1940. A 1939 Field Gr has .662 and 2 9/16" chambers with the new Single Sighting Plane.
10 ga. was from what I can see .775 until discontinued and 2 7/8" chambers from 1886.
