a two piece , two - stage , rechargeable , reusable , reduced - energy mechanically operating cartridge is provided for launching a bullet of various compositions from a dedicated or modified firearm . the cartridge unit is comprised of a primary case , a piston sleeve , a propellant unit , and a bullet choice of a solid light weight material for inanimate - target applications or a “ marking ” version for non - lethal live - target training applications . cartridge includes a piston sleeve and a primary case coupled together via a channel and cog locking / traveling / unlocking system . the primary case includes a substantially non - deformable jacket defining a cavity to receive a propellant unit or propellant connection and provides the channels to receive piston sleeves cogs for a locking / traveling / unlocking feature . the piston sleeve includes a substantially non - deformable jacket defining a cavity to receive configured bullet . the primary case also includes a substantially non - deformable jacket for being axially coupled with the piston sleeve , and for coupling with a propellant mechanism . upon activation of the mechanically operating cartridge within the chamber of the firearm during stage 2 , the piston sleeve and primary case telescope apart from a compressed , static , stage 1 position forcing the firearm &# 39 ; s slide or bolt to the rear , a mechanical operation opposed to a conventional cartridge with gas blow back operations . spent cartridge is reused by manually separating piston sleeve from primary case as to remove spent propellant unit with removal tool , recharged with new propellant unit reloaded with choice of bullet composition and placed into magazine or similar for firearm loading .