There is a Francis Sansing living in 1860 & 1870 Neshoba County where this company was raised. He was living in Henry County, GA in the 1850 Census.

He may have also served with this unit.

Francis Sansing (First_Last)
Regiment Name 1 Mississippi Cavalry Reserves
Side Confederate
Company D (Raised in Newton County)
Soldier's Rank_In Private
Soldier's Rank_Out Private
Alternate Name
Notes
Film Number M232 roll 35

A capsule history of this unit can be found at this URL.
http://mississippiscv.org/MS_Units/1st_Bn_MS_CAV_RES.htm

The family researcher at this site provides data for this man.