Miss. Code Ann. § 33-7-113

The Adjutant General shall publish annually a relative rank list of all officers in the Mississippi National Guard. Commissions or warrants of officers shall bear date of actual appointment by the Governor. Officers of each grade shall rank and take precedence according to the date of federal recognition of their respective commissions or warrants, and when two or more of the same grade are of the same date, their rank and precedence shall be determined by the length of service, continuous or otherwise, in the Mississippi National Guard or in the Armed Forces of the United States; and if for equal service, then by age, the older being the senior, provided, that an officer will not be credited with time spent on the state reserve or retired list in determining his lineal rank in the active list.