this disclosure relates to a method and an arrangement for low or non rotating artillery shells fired from launch weaponry and which introduces a portion of the barrel pressure built up in the barrel during the launch phase into a chamber arranged in the low or non rotating artillery shell which is delimited in at least one direction by an element which is movable relative to the rest of the shell when a differential pressure between the chamber and the external environment of the shell is sufficient to move the element the moveable element may be a protective casing covering fins of the artillery shell application_number US 90730105 A description the missile shown in fig1 in this case the shell 1 a is provided with a band track 2 for a drive band which is conventionally known as a u201c skidding drive band u201d which is generally lost when the shell leaves the barrel in order to effect low inherent rotation or no rotation of the shell a number of deployable fins 3 are shown fully deployed in the figure and which are fixed on a body part 4 which rotates freely relative to the rest of the shell about an axis concentric with the longitudinal axis of the shell the dividing plane between the shell 1 and the body part 4 has been labeled 5 in addition the shell 1 has two.