“Just as you turn the bull's-eye on any place which you are not quite sure of, so a flare-light is sent up when either side suspects evil designs on a particular part of their trench-line.”
The Adventure of Living John St. Loe Strachey
Basic Information
An illuminating round is a round of ammunition designed to produce light and illuminate the target area. In almost all current and historical cases illuminating rounds are some form of pyrotechnic1. These are generally fired from large calibre weapons so as to provide a significant volume of pyrotechnic material - mortars and artillery are favourites but hand fired, single shot rockets are also quite common and some manufacturers produce illuminating rounds for grenade launchers and/or as rifle grenades. An illuminating hand grenade is more commonly known as a flare.
Early illuminating rounds - known as carcasses - varied very little from contemporary incendiary rounds, except for the occasional addition of substances to make them burn brighter. Modern devices tend to be powerful magnesium flares with an integral parachute designed to keep them aloft as long as possible.
It is worth noting that the illumination provided by these rounds is typically harsh and unlike natural light, so that despite its brightness it can be surprisingly hard to make out what it is illuminating - especially if it is not moving.
A final illumination device is the trip flare - effectively an illuminating round designed for use as a non-lethal booby trap. When triggered it bursts (some designs even bound into the air first) and lights up the area around it, revealing whatever it was that tripped the flare.
This category could probably also be extended to include signalling pyrotechnics - coloured flares which are fired to communicate messages over a wide visual range - although these usually dispense coloured smoke as well as light to aid visibility in daylight. The most frequent use for these is the civilian red distress flare, but historically they were widely used for battlefield signalling as well.
Sources
Game and Story Use
- Particularly determined characters will get around to using these as a weapon - especially against anything that needs to be killed with fire.
- …or anything that doesn't like light. Theoretically you might even be able to create a flare that generated specific wavelengths of light (say a UV flare to annoy vampires).
- Setting these off in a confined space is usually a really bad idea.
- Makes a decent "wandering monster" for a warzone at night - the sudden illumination of the PCs unit by a dirty great flare - even if no-one actually fires on them, it should still be unnerving2.
- Trip flares are much the same - even if the people who posted them are long gone (if they aren't your annoyance may be extremely short lived), and even if you are grateful at least that that wasn't a grenade trap or land-mine on the other end of that trigger, no-one likes being suddenly lit up at night.