..Chambers, by the way, appear to be 2 3/4". I see no marks except the serial number on the underside of the barrels, so I assume the only way to figure out the chokes is to gauge the muzzles or pattern the gun. McIntosh says the barrels were taper-bored from breech to muzzle rather than choked near the muzzle.
Glad the pictures helped. Chambers should not be 70mm unless they have been reamed. As for choke, you are correct, they need to be patterned. Here is an ad from 1911, guess what chokes produced this.
Gordon,
Nice "I" grade.
Pete
