Abstract: An improved and repetitively operable gaseous-propellant gun system for lching one or more projectiles to strike a target, especially a relatively high-speed target at close range. The system is generally made up of a housing having a chamber therein with enlarged and reduced chamber portions. A double-acting piston includes enlarged and reduced tandem pistons for advancement in opposite directions within the chamber. A gaseous source means controls the admittance or release of a lightweight gaseous medium to the reduced chamber portion. A projectile support and handling arrangement functions to securely position a projectile in the barrel bore. A forced air inlet and exhaust subassembly not only admits a first volume of air to be compressed between the enlarged piston and the housing but also admits a second volume of air between the enlarged and reduced pistons so as to biasingly urge the double-acting piston towards the enlarged chamber end of the housing.

Abstract: An apparatus for injecting a signature signal on a magnetic tape comprising signature signal generator connected to a switching system. The switching system connects the signature signal to the recorder inputs while disconnecting the normal recorder inputs. A timer is located in the switching system to permit the injection of the signature signal for a specific time period.