Kathy1 A nice Island locks back action version with a re-proof at .740 things cant get any better. The 81 and 16 stamps on the barrels a consensus of opinion on this it is some form of barrel makers identification because there where four guns ordered in this set so it could stand to reason that some form of identification may have been needed for the number of tubes or completed barrels. Though I am always open to suggestions to some other reason for these numbers, I would dearly like to find another gun from this set made for Henry Chaplin just to compare but I have never found another owner to date.