Service ammunition. Ammunition for combat use. This ammunition is approved for service use. It contains explosives, pyrotechnics, or chemical agent filler. The propellant, if required, is of service or reduced charge weight. Service ammunition is also called  tactical ammunition. Warhead. The part of ammunition containing the materials intended to inflict damage. The explosives in warheads are called the  payload. Airborne stores. Items that are NOT normally separated from the aircraft in flight. A partial list of these items includes tanks, pods, and non-expendable training weapons. Targets, racks, launchers, adapters, and detachable pylons are also included. Q8-1. What  aircraft  equipment  uses  cartridge- active devices (CADs)? Q8-2. Define the term incendiary. Q8-3. What are airborne stores? THE FUNDAMENTALS OF EXPLOSIVES LEARNING OBJECTIVE: Recognize the fundamental concepts of explosives, the potential hazards associated with weapons,  and  the  identification  and marking of ammunition. You should know the difference between an explosive and an explosion. An explosive is a material that is capable of producing an explosion by its own energy. There are many definitions of an explosion. Dr. Tenney L. Davis gave us the only simple definition: an explosion is "a loud noise and the sudden going away of things from the place where they have been." Another definition states "an explosion is a rapid and violent release  of  energy,  not  necessarily  involving  an explosive substance." For example, in the explosion of a boiler, the water is not an explosive substance. In this chapter, an explosion is defined as "a chemical decomposition or transformation, with the growth of heat and the formation of decomposition products, sometimes producing gas." All explosives in military use produce gas, so this definition is correct, though a chemist might not agree. If ammunition is to function at the time and place desired, you must use the right type of explosives. Each has a role, either as a propellant or as a bursting charge. Explosives suitable for one purpose may be entirely unsatisfactory for another. For example, the explosive used to burst forged steel projectiles is unsuitable for ejecting and propelling the projectile. Normally, the more sensitive the explosive, the smaller the amount used. Similarly, the explosives used in initiators, such as primers and fuzes, are so sensitive to shock that only a small quantity can be used safely. HIGH AND LOW EXPLOSIVES There are two general classes of military explosives—high explosives and low explosives. Each is classified according to its rate of decomposition. High and low explosives may be further classified by their reaction, composition, or service use. However, only the two general classes, high and low, are covered in this chapter. High Explosives High explosives are usually nitration products of organic substances. They may contain nitrogen and inorganic substances or mixtures of both. A high explosive may be a pure compound or a mixture of several compounds. Additives, such as powdered metals, plasticizing oils, or waxes, provide desired stability and performance characteristics. A high explosive is characterized by extremely fast decomposition called detonation. A high explosive detonates almost instantaneously. The detonation is similar to a very rapid combustion or a rupture and rearrangement of the molecules themselves. In either case, gaseous and solid products are produced. The disruptive effect of the reaction makes some explosives valuable as a bursting charge. This bursting effect prevents its use in ammunition and gun systems because the gas pressures formed could burst the barrel of a weapon. Low explosives Low explosives are mostly solid combustible materials that decompose rapidly but do not normally explode. This action is called deflagration. Upon ignition and decomposition, gas pressures develop to propel something in a definite direction. Ammunition, gun systems, and some missiles use this type of explosive. The rate of burning is an important characteristic, which depends on such factors as combustion gas pressure, grain size and form, and composition. Under certain conditions, low explosives may react in the same manner as high explosives and explode. 8-2