Posted by John Harris on July 22, 2008, 7:02 pm, in reply to "Re: Shortened Barrels"
According to page 394 in the Houchins book
16 gauge chokes are approximately: .662 Bore .657 Imp Cylinder .639 Modified .629 full
"The actual choke in the barrel was a tapered cone about 1 1/2 inches to 2 inches from the bore diameter to the choke diameter. The choke diameter at the muzzle was straight for about 1 inch."