Drew, thanks once again for your time and effort on accidents like these. It's something all of us who shoot old shotguns need to think about.

I have a number of once fired Herter's 16ga hulls on hand. Like virtually all 2 3/4" shells, they're a little short of that mark--but not much. I get them at about 1/32" short of 2 3/4". So definitely longer than what was probably an original 2 9/16" chamber (possibly lengthened).