Abstract: A decoppering agent for incorporating into a propellant to remove copper from the rifling of the internal bore of a gun barrel. The decoppering agent comprises a lead-free pulverized additive mixed together with the other propellant compounds and comprises a mixture of tin and bismuth.

Abstract: The present invention relates to a method and an apparatus for producing rapid cross-ignition of preferably elongate powder or pyrotechnic charges, such as the propellant charges in impulse motors for correcting the trajectory of shells, rockets and missiles. The cross-ignition is produced by initiation of an elongate, extremely fast-burning or detonating primer charge with an extremely low explosive force which has been arranged in contact with at least part of the periphery of the propellant charge. The primer charge forms a tube whose cross-ignition effect is advantageously complemented by an inner, slower burning powder core which is combusted with deflagration.

Abstract: The invention relates to a method, and to an arrangement, for optimizing the operation of a door closer at different phases of opening and closing of the door. The door closer is provided with a force transmission shaft (1) turning in accordance with the movements of the door and with a spring element (2) operationally connected thereto. The opening of the door takes place against the force of the spring element (2). According to the invention, at the closing phase of the door the energy of the spring element (2), exceeding the return force of the spring element (2) needed to accomplish the desired closing movement of the door, is recovered through simultaneous braking of the closing movement of the door for the main part of the closing movement. When the door is only somewhat open any more, preferably under 5.degree., a final force securing the closing of the door is accomplished by making use of said recovered energy.