since cannon balls rusted and scaled in damp storage conditions, the gunners used a shot gauge, a round 'ring on a stick', if the shot passed thru the gauge, it was usable. casting in those days would have been in sand moulds and defective pours would have been common. i'm still surprised that there are no apparent mould lines or sprue marks. cannon balls were never machined post casting other than to knock off the sprues and/or flashing where the metal had been poured. shot was invariably a loose fit. the wadding helped cut down the windage.
|