Abstract: A shotgun, such as a pump shotgun is retrofit with a kit that neutralizes or counters the recoil associated with firing the shotgun. The kit includes either a mechanical system or an electrical system or an electro-mechanical system and is activated by sensors or elements on the shotgun to deliver impact energy to the shotgun in a direction opposite to that of the recoil energy and at a time that is selected to most effectively neutralize that recoil energy. One form of the impact-delivering system includes a spring-biased weight that impacts a stop on the shotgun, and another form of the system includes a solenoid-controlled impact-delivering weight. A third form has a spring-assisted plunger of a solenoid-controlled impact-delivering element. The sensors are connected to the impact-element releasing system by a circuit that can include a sensitivity setting element whereby a user can adjust the sensitivity and/or the timing of the system to meet his or her needs and to account for changing conditions.

Abstract: A shotgun, such as a pump shotgun, has the recoil thereof controlled a spring system. The shotgun includes a breech bolt that is locked to an operating arm during cocking, but is then released from that operating arm when in the battery location and is held in the battery position by the spring system. The spring system includes springs that are engaged with an element that moves in response to the firing of the shotgun, and are sequentially released from that moving element as that element recoils. One form of the invention includes a pump shotgun in which the breech block moves in a recoil movement in response to firing the shotgun, with the springs engaging the moving breech block and sequentially disengaging from that moving breech block.

Abstract: A telephone set which is being used as a pushbutton-type telephone is protected from unauthorized use by a frequency signal altering circuit restricting the output from a built-in TOUCH-TONE (R) signalling pad or other TOUCH-TONE (R) generator. The circuit includes at least one notch filter which, when electrically inserted between the telephone set and a call receiving station, alters at least one of those frequencies generated at the telephone set by pushbutton circuits to dial a number to a form which is not proper for actuating equipment at the call receiving station. The frequency signal altering circuit is located internal to or closely adjacent the telephone set to be protected. Circuits which restrict the output from a telephone are also disclosed.