1. A PROJECTIBLE COMPRISING A BODY HAVING AN AXIAL TUBE THEREIN, MOVABLE MEANS HOUSED AT LEAST PARTIALLY IN SAID AXIAL TUBE, STABILIZING SURFACES CARRIED BY SAID MOVABLE MEANS, OPERABLE MEANS FOR EXTENDING SAID MOVABLE MEANS FROM THE REAR OF THE PROJECTIBLE AFTER THE LATTER HAS BEEN FIRED SUCH THAT THE STABILIZING SURFACES ARE SUPPORTED REARWARDLY OF THE PROJECTIBLE FOR GUIDING THE LATTER IN FLIGHT, THE RADIALLY OUTWARD EDGES OF SAID STABILIZING SURFACES BEING CONTAINED WITHIN A CIRCUMFERENCE NO GREATER THAN THAT OF THE PROJECTIBLE BODY, SAID MOVABLE MEANS COMPRISING A SPINDLE SLIDABLE IN SAID AXIAL TUBE, SAID SPINDLE HAVING AN ENLARGED PORTION OPERABLE TO ENGAGE A BUSHING CARRIED IN SAID AXIAL TUBE TO STOP THE SPINDLE IN ITS EXTENDED POSITION, SAID BUSHING HAVING A LONGITUDINAL PASSAGE FOR RELEASING A BRAKING FLUID CONTAINED IN THE AXIAL TUBE EXTERIORLY OF THE SPINDLE AS THE ENLARGED PORTION ON THE SPINDLE ACTS ON THE BRAKING FLUID UPON EXTENSION OF THE SPINDLE WARDLY OF THE PROJECTILE.