Abstract: This invention relates to new and improved methods and apparatus for effeating recoil and counterrecoil movement of the gun tube of a weapon system wherein a movable piston sleeve concentric with and movably connected to the gun tube defines a pressurizable compressible fluid chamber with the stationary cradle of the weapon system and carries a piston head which separates the chamber into two compartments, a muzzle compartment and a breech compartment, and which defines with the interior wall of the cradle an annular fluid throttling orifice to cause energy dissipation during movement of the piston. The piston sleeve is separated by the piston head into two sections of different diameters, the larger diameter section being located on the muzzle compartment side of the chamber so that compressed fluid, at the termination of the recoil cycle acting on the piston, may initiate counterrecoil movement of the piston and gun tube as a result of the force differential in said compartments.