A floating barrel gun design, a design in which a propellant gas discharge is used to counterbalance the recoil force of the gun, has been improved to include a novel automatic mechanical mechanism which allows the floating or inner barrel to be held stationary within the gun while the gas is discharged and after the discharge is complete, the barrel is released to return to its pre-actuation position. The discharge of gas is also made safer by an automatic mechanical mechanism for venting the accumulated gas, and this mechanism is activated as the projectile leaves the gun. The mechanism requires that the gas be discharged into the interior of the gun and the recoil-countering gas streams be directed toward a rearward moving breech block. The gas is discharged automatically during the firing cycle, as the firing chamber pressure falls upon the projectile exit, by venting the compressed gas through passageway nozzles which proceed through the annulus of the floating barrel and are controlled by rotatable metal plates. The discharged gas ultimately exits the gun through spaces in the outer barrel which open to the gas as the breech block moves rearward. To explain the invention, the operating of a handgun is described as the preferred embodiment. The handgun is a result of an integration of the ideas concerning a floating barrel delivery system with conventional ballistic designs.