Abstract: An artillery simulator apparatus is provided including a gun tube which is swingably mounted to a rotatable cab. During simulator recoil and counter-recoil, the gun tube is held in fixed position while the breech moves under computer control from an "in battery" position to a recoil position and then back to the "in battery" position. Breech recoil speed and stroke are controlled to simulate actual M109 breech performance based on propelling charge, type round, and gun tube elevations. A double acting hydraulic cylinder is attached to the breech to drive the breech in the recoil and counter-recoil directions. During recoil and counter-recoil, the hydraulic cylinder is positively driven by fluid from the same hydraulic source. The simulator includes sensors for determining the type of round placed in the breech, the round fuse type and run time setting, the firing primer, as well as the level of propelling charges in the breech.