US Army or USAF EOD would be willing to check it for you. 10-12 years ago they disarmed a War 2 vintage training rocket found in a field it was done free of charge.
Sounds like a Model 1841 6 pounder Sperical Case shot... If he starts shaking it or picks up a drill I'm headed FAR away. It may well still be live and can be quite dangerous.
"A" on the fuse might refer to an Augusta Arsenal produced time fuse. Bormann fuses were more likely to go off while the
CSA fuses had a tendency toward poor quality control early in the War.
typical 6 LBS spherical case: weight 4 lbs diameter 3.58"
Good Luck