Review the history of the 5th Miss. For a brief time at Shiloh these men fought with the 7th Mississippi and were part of Chalmer's "High Pressure Brigade". His records may be located with the 8th Battn. Miss. Inf. since I believe that's what they were called after consolidation at Atlanta in 1864.

http://mississippiscv.org/MS_Units/5th_MS_INF.htm