Abstract: A stackable insert for use in organizing the family members in a family of top opening military type ammunition boxes wherein each family member has the same base dimensions but a different height than other members in the family of boxes. The insert includes a rectangular shaped open top container and a flat lid that is hinged to one side wall of the container and secured at closure by a positive snap over latching mechanism. A pair of finger holes, or other lifting means, are provided in the lid which provides for easy lifting of the insert. A panel type separator divides the container into compartments. The insert is dimensioned so that a plurality of inserts can be stacked in each member sized ammunition box to maximize the usable space within each size box.