100 years ...easy .
A shell from the siege at Port Hudson , a fort on the Mississippi River from 1865 was dredged up in river sand and deposited at a construction site , Fuse was intact and shell not exploded ...they were filled with black powder and round lead balls , the fuse was usually ignited during firing of the shell and the shell would explode inside or above a fortification ... this one didn't ... the bomb squad was called and they hauled it off for safe disposal ... it exploded after being in river sand since 1865 ,,,which surprised me but didn't surprise them !
This was about three years ago ...the bomb squad guy said black powder shells were very dangerous and if you had any ...call him .
I only have shell fragments but I know some people that have complete shells and they need to make sure the fuse and powders has been removed .
Gary

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