higher velocities for the 40 mm projectiles in the m320 the 40 mm m320 gun sleeve cartridge case 10 allows for a new generation of 40 mm ammunition to be designed with extended range guidance with more accurate lethality the 40 mm m320 gun sleeve cartridge case 10 can be longer than the m320 tube and therefore provide more efficient use of propellant load to provide higher velocity and extended range without increased pressures in the gun tube the gun sleeve cartridge case 10 can be lengthened hence to provide more velocity hence to provide enhanced range yet without appreciably increased recoil to the shooter when firing the launcher as might have been feared with a longer tube because the impulse caused by the amount of burning propellant is not changed even though the length of the gun sleeve cartridge case 10 may have been increased the 40 mm m320 gun sleeve cartridge case 10 is applicable to other rifled medium caliber and shoulder launched weapons and can be used to provide no spin for guided projectiles higher velocity and extended range without increased pressures in the gun tube the 40 mm m320 gun sleeve cartridge case 10 allows for 40 mm rounds to be launched without spin and therefore the explosive shape charge jet liner does not require the use of costly and difficult to manufacture flutes on the shape charge liner as compared to rifled spinning projectiles with shape charge liners the 40 mm m320 gun sleeve cartridge case 10 allows for extended range of 40.