My family owns a bunch of acres up the Big Black River, including Thompson's Ridge where Confederate artillery battery was located, along with sharpshooters, etc. Great metal detecting area, and I remember us unearthing one of the abandoned guns in the mid-60s during deer season. You can still see the depressions for the 4-piece battery that was located there.
Anyway, I have spent some time in the museum in Grand Gulf, and have found pix of some of my kin in their uniforms who were in the Jefferson Flying Artillery! Great little musuem, and they rotate exhibits about every 3-4 months.