Using the CWS&S at http://www.itd.nps.gov/cwss/soldiers.htm I found this listed under Copnfederate Troops

M. Vaughn (First_Last)
Regiment Name 2 Confederate Engineer Troops
Side Confederate
Company B
Soldier's Rank_In
Soldier's Rank_Out
Alternate Name
Notes
Film Number M818 roll 24

There are several M. Vaughns in Ala. units but only one in a Mississippi unit. H. Grady Howell does not list a "M" Vaughn in his roster.

M. Vaughn (First_Last)
Regiment Name 1 Batt'n-State Troops, Miss. Inf. (12 Months, 1862-3).
Side Confederate
Company D
Soldier's Rank_In Private
Soldier's Rank_Out Private
Alternate Name
Notes
Film Number M232 roll 41

George