Original British Napoleonic Royal Navy Gunner's Cannonball Calipers from H.M.S. Northumberland (1798) colts There are 5 possible markings:

There are 5 possible markings:

30-06 rimless cartridge

And also (mixed up with German): Buren

" with the serial number 18839 stamped below

/ FRANKFURT/M

Original British Napoleonic Royal Navy Gunner's Cannonball Calipers from H.M.S. Northumberland (1798) colts There are 5 possible markings:Original Item: One of a Kind Set. These are extraordinary, being British Naval Gunner's Calipers for measuring Cannon Balls aboard ship during the Napoleonic Wars. Measuring 26" on each leg, these measured the diameter of the large Cannon Balls, ensuring they are delivered to the correct sized Cannons from the Storage Magazines. One leg bears a brass plaque on one arm simply stating: H. M. S. Northumberland H. M. S. Northumberland was built in 1798 at