A high velocity actuator, which may be used as a blast simulator, is provided with an actuator cylinder tube having an opening at first and second cylinder ends, and an actuator piston rod slidably mounted within the actuator cylinder tube and extending through the opening in the first cylinder end. A control valve concentric to the actuator cylinder tube is configured to be coupled to a source of pressurized fluid and controls admittance of the fluid under pressure to the actuator cylinder at the second cylinder end to act on the actuator piston rod to extend the actuator piston rod towards the first cylinder end.