In the second picture posted, the barrels are marked Choke 16.9. 16.9=.665 which I assume would be nominal bore size. After 1924 how do you know what the choke is? Do the markings indicate cyl/cyl? I wouldn't think so. I don't have the gun in hand yet so there may be additional markings not seen in the pic.

Edit
Figured it out.(I think)
After 1924
"Diameter of choked bore no longer indicated"

Last edited by ithaca1; 10/15/15 05:53 PM.
Bill Johnson