Mortar training ammunition device having independently rotatable vent closure rings

A mortar training ammunition device, comprising

• (a) a projectile having a longitudinal axis;
• and
• (b) a propulsion module connected with said projectile, said propulsion module including
• (1) a cylindrical tube coaxial with said projectile and containing a plurality of openings adjacent to an end of said tube remote from said projectile, said openings being arcuately spaced about the circumference of said tube and being arranged in a plurality of longitudinally spaced groups;
• (2) means for selectively opening and closing said groups of openings comprising a plurality of rings rotatably mounted on said tube and containing a plurality of arcuately spaced openings, whereby said rings can be independently rotated to align said vent openings with said tube openings and to block said tube openings to allow for employment at various ranges;
• (3) at least one propelling charge having a partial annular configuration and arranged in contiguous relation with the outer surface of one of said rings;
• and
• (4) propulsion means arranged in the other end of said tube adjacent to said projectile, whereby when said rings are rotated to selectively open said groups of openings and when said propulsion means are activated, gases are generated in said tube and expelled from said open groups of opening to ignite a propelling charge associated with said opened group of openings and propel said projectile toward a target.