The Mk 31 Mod O projector is operated as follows:
1. Remove the bandoleer and projector from the plastic envelope.
Figure 1-15.-The Mk 79 Mod 0 illumination signal kit.
2. Cock the firing pin of the projector by moving the trigger screw to the bottom of the vertical slot and slipping it to the right so that it catches at the top of the angular (safety) slot.
The plastic tabs over the signals in the bandoleer protect the percussion primers from being struck accidentally. They should be kept intact until just before loading the signal into the projector.
3. Break the protective plastic tab away from the signal in the bandoleer to allow attachment to the projector.
4. Mate the projector with the signal and rotate the projector clockwise until the signal is seated.
5. Hold the projector over your head with your arm fully extended. The projector should be pointed at a slight angle away from the body.
6. While firmly gripping the projector, fire the signal by slipping the trigger screw to the left out of the safety slot and into the firing slot.
This action should be one continuous movement so that the thumb does not interfere with the forward motion.
7. If the signal fails to fire, pull the trigger screw back to the bottom of the firing slot against the force of the spring, and lift your thumb quickly.
When removing a misfired cartridge, ensure that you keep it pointed in a safe direction and do not place any part of your hand over the discharge end of the cartridge.
8. Unscrew the spent signal case or signal that has failed to fire and discard it by throwing it over the side.
9. Place the trigger screw in the safety slot and reload, as in step 4, if you need to fire another signal.
The following special safety precautions apply when using the Mk 79 kit:
1. Signals in this kit are ignited by percussion primers, which should be protected against being struck. Protruding tabs of the bandoleer, which extend over the signal bases, prevent accidental striking of the primers. They should not be torn off or bent back except in loading a signal into the projector.
2. The projector should not be loaded until immediately before firing. If a signal is loaded into the projector and is not fired immediately, it should be returned to the bandoleer.
Dented or damaged signals should not be used. Dents or other imperfections might result in violent actions of the signal when fired.
3. Signals should be inspected periodically to ensure that they are not dented or otherwise damaged.
4. Signals should be kept away from fire and other heat sources.
5.The projector trigger screw should be checked frequently to ensure that it is tight. A loose trigger can release the firing pin prematurely and cause injury, or it might fall out and be lost during emergency loading, thereby rendering the projector useless.
6. The trigger screw should be in the safety slot while a signal is being loaded.
7. In the firing of the projector, care should be taken to raise the arm well above the head with the projector held in a vertical position. A loaded projector should never be pointed toward other personnel or toward the body of the user.