stage reduced energy cartridge of the preferred embodiment these figures illustrate a first assembly of the cartridge into stage 1 static condition through stage 2 dynamic condition upon activation or discharge and then through uncoupling and recoupling again into a recharged reloaded stage 1 static cartridge for reuse fig7 a illustrates coupling of components in an exploded view of the two stage cartridge of the preferred embodiment the components shown include the primary case 2 and piston sleeve 4 along with the projectile 6 8 and primer cartridge 50 the arrows indicate how the components are coupled together the projectile is u201c loaded u201d straight into the projectile cavity of the sleeve 4 and the primer cartridge 50 is u201c charged u201d directly into the primer cavity of the primary case 2 the primary case 2 and piston sleeve 4 are first axial coupled straight together with cogs 12 a of the case 2 matching channels of the sleeve 4 and or vice versa then the two 2 4 are relatively rotated finally the two 2 4 are further compressed together axially cogs of the sleeve 4 matching channels 14 of the case 2 until the stage 1 static position is reached fig7 b illustrates the cartridge in static condition stage 1 fig7 c illustrates the cartridge in dynamic condition stage 2 one arrow indicates that the projectile moves straight away from the piston sleeve 4 another arrow indicates that the primary case 2 move straight rearward from the piston sleeve 4 the piston sleeve is indicated as remaining in a same position.