An apparatus for non-permanent conversion of a semiautomatic pistol into a compressed gas powered weapon simulator. The apparatus replaces the pistol's barrel, recoil spring and magazine with no modification of the pistol, which allows retaining the operational functions of the pistol's remaining components. Compressed gas, from the simulation magazine unit, is used in the compressed gas valve means, in the barrel unit, to operate the slide mechanism, to compress the simulation recoil spring, and to emit a laser pulse beam on a target when activated by the firing mechanism; and battery power, from the simulation magazine unit, is used to count the number of shots, lock the slide after a predetermined number of shots and transmit information from the weapon simulator to a remote data system. The compressed simulation recoil spring returns the slide mechanism back to its original position, unless locked open by the apparatus.