Abstract: A method and apparatus is for imparting, in a continuous sequence, a predetermined rotational movement to a warhead releasably housed in a protective canister and ejected out in ballistic ejection trajectories from the canister. The canister is spun to the desired rotational speed by flow of combustion gases through gas outlet nozzles discharging in the outer periphery of the canister and supplied from a central combustion chamber in which a propellant powder charge is combusted. The combustion gases are then led from the combustion chamber, in the final phase of the propellant charge combustion, through gas outlets facing towards the warhead and initially covered by the propellant charge and exposed as a result of the combustion, for ejecting the warhead out of the canister.