CHAPTER 1

EXPLOSIVES AND PYROTECHNICS

As you begin the study of the Gunner's Mate rating, you are taking the first step in joining a proud tradition of over 200 years of service. As a Gunner's Mate, you and your equipment represent the offensive power of the U.S. Navy's surface fleet. As you move into the petty officer ranks, you will wear the title of "Gunner" to all those who know and respect the responsibilities of your profession. This training manual provides a condensed version of the responsibilities and basic knowledge required of your specialty. Throughout the text, you will find References to other manuals for further study. These References are crucial to your success both on the deck plates and in competition for advancement in rate. Seek them out and become familiar with their contents.

One very important development in the history of ordnance was the discovery of explosives. In this chapter, we will discuss the fundamental characteristics of explosives and how they are classified according to their use. Then we will go into some details of various explosives and pyrotechnics used in Navy ammunition. We will conclude this chapter with a discussion of some general explosive safety requirements.

WARNING

DO NOT attempt to operate any explosive or pyrotechnic device until you are thoroughly trained and certified on that device. The information contained in this training manual should not be used to replace source publications or prescribed training procedures.

EXPLOSIVES

LEARNING OBJECTIVE Describe the characteristics and classification of explosives and propellants of naval ordnance.

To understand the composition and function of a complete round of ammunition, you need a basic knowledge of the characteristics and uses of military explosives. The demands for ammunition capable of fulfilling the many requirements of the Navy necessitates the employment of several classes of explosives. Each explosive performs in a specific manner and is used for a specific purpose. Therefore, explosives used to burst a forged steel projectile would be unsuitable as a propelling charge for ejecting and propelling projectiles. Similarly, the explosives used in initiators, such as in primers and fuzes, are so sensitive to shock that only small quantities can be used safely.

NAVSEA OP-4, Ammunition Afloat, defines the word explosives without further qualification as those substances or mixtures of substances that when suitably initiated by flame, spark, heat, electricity, friction, impact, or similar means, undergo rapid chemical reactions resulting in the rapid release of energy. The release of energy is almost invariably accompanied by a rapid and pronounced rise in pressure and temperature. The rise in pressure usually, but not necessarily, is a consequence of the rapid generation of gas in a much larger volume than that originally occupied by the explosive.

An "explosion" is defined as a practically instantaneous and violent release of energy. It results from the sudden chemical change of a solid or liquid substance into gases. These gases, expanded by the heat of the chemical change, exert tremendous pressure on their containers and the surrounding atmosphere.