Abstract: A long range artillery shell having a rocket motor which comprises a combustion chamber (shown filled with solid propellant 9, burn inhibitor 10, igniter material 13 and propellant support 11,12) which has at one end a plenum chamber 8 and a rocket nozzle 14 for venting the plenum chamber 8. The propellant 9 is arranged in an end-burn configuration and housed within the combustion chamber and the propellant support 11,12 is located between the propellant 9 and the plenum chamber 8 and is capable of preventing entry of unburnt propellant into the plenum chamber 8 while permitting, in use, the substantially unhindered transfer of propellant combustion products to the plenum chamber 8.