Abstract: A gun-launched projectile with a chamber for generation of combustion gases from a propellant grain is disclosed. The chamber is arranged with at least one gas outlet in its base plane, said propellant grain having a burning area, mass and static burning rate so related with the area of the gas outlet/outlets, that a low mass flow of gaseous combustion product is operable to continue from the time of muzzle exit for a considerable portion of projectile flight and to provide a substantial decrease in base drag with a concomitant increase in projectile range. The pressure in the combustion chamber during flight only slightly exceeds the base pressure in an amount of 0.01 to 0.5 bar.