Pyrotechnics, delay trains used

Delay trains used in pyrotechnics are described in Section 4, Part F... 

The flash dets are used in fuze trains preceded by some nondetonating burning element, such as a percussion cap or pyrotechnic delay element. They are used mainly in mechanical out-of-line safe-and-arm fuze trains and serve the purpose of both explosive relay and detonator. 

Since percussion primers are used for initiation of explosives as well as ignition of propellants in small guns and gas cartridges, and also for purely pyrotechnical initiation such as of pressed delay trains and section charges, the formulations vary with the purpose, though some formulas are said to be equally applicable to detonation or ignition. In other cases, low-violence and low-gas formation are claimed to make the primer especially useful for pyrotechnic ignition. 

Fuse A train of pyrotechnic composition (usually black powder), often covered with twine, thread, or twisted paper, as well as waterproofing material. Fuses are lit by a safety match or other hot object, and provide a time delay to permit the person igniting the device to retreat to a safe distance. This term should not be confused with fuze, which is a device used to initiate a military explosive device such as a bomb. 

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