Ron: There are some chamber length gages available from Galazan that work well and are inexpensive. They are like a jacknife and will measure several gages and chamber lengths by just opening them up to the right gage and poke them into the chamber till they stop and reading the measurement. Lacking this, if you have a small machinist scale or ruler that will go into the chamber you can set a light to shine into the muzzle end of the barrels and push the scale in until you see it touch the end of the chamber where the forcing cones start. This will be the first "ring" you see down in the chamber looking from the breech end. Just hold it there and see what the scale reads when it's square to the breech. Sometimes with a machinist scale that is thin you can slide it down the chamber wall and actually "feel" it stop or raise up at the end of the chamber. I would almost assume you are looking at 2 5/8" with that vintage gun, and the scale method should be accurate enough to verify it. Regards! Lee.
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