Not to add to any potential confusion, but here at the National Civil War Naval Museum in Columbus, GA, we have some artillery rounds recovered from the wreck of the Chattahoochee and all of them are either 32 pounders from two 6.4 inch old timey guns, or nine inchers. They are all explosive rounds from what we understand was a nine inch Dahlgren. My predecessor here told me that it was transferred to Atlanta for the city's defense. Hope this helps.