Cannon system training apparatus employs a double acting hydraulic cylinder controlled by an electrically operated directional control valve which controls the supply of hydraulic fluid to the double acting hydraulic cylinder in such a manner as to cause the gun tube to execute a recoil/counterrecoil cycle similar to that which would occur during an actual firing of the cannon system. A counterrecoil accumulator stores energy in the form of pressurized hydraulic fluid expelled from the hydraulic cylinder during recoil for counterrecoiling the gun tube. The gun tube is formed to enable dummy projectiles and simulated propellant charges to pass easily through the gun tube and to be ejected from the muzzle end by the ramming system employed.