A mobile remotely controlled robot includes a robot platform and a robot arm maneuverable with respect to the robot platform. A housing is configured to be removably mounted to the robot arm. A sleeve is translatable with respect to the housing for receiving a weapon therein. There is a gear rack on the sleeve and a pinion gear, rotatably disposed in the housing, is engaged with the gear rack. A braking subsystem resists rotation of the pinion gear when the gear rack translates upon firing of the weapon.