Also that 2 3/8" sounds a bit questionable on the chamber length. 2 9/16" w2as the older standard for US made 16's not 2". It has be3en mentioned numerous time here about American guns being intentionally chambered 1/8" short but I believe this was primarily Parker & mostly in 12 ga only.
Are you certain you measured to the exact end of the chamber. If you are measuring with a standard chamber plug gauge you may want to check the end diameter of the gauge in comparison with that of the chamber. The chamber has a taper in it of approximately .005" per inch. "IF" the forward end is even .001" smaller than the gauge (not uncommon at all in older guns) the gauge will reads it as being .200" short.
