Cordites

a mainly high-nitrogen nitrocellulose-based powder plasticized by nitroglycerin and a highly volatile solvent (for example, acetone or an alcohol-ether mixture), used for making ammunition for small arms, artillery, and mortars. The compositions of various cordite powders are shown in Table 1.

Cordites have certain advantages over pyroxylin powders in a volatile solvent, including (1) lower sensitivity to changes in atmospheric humidity and greater ballistic stability, (2) diminished contraction of the powder elements, so that they hold their form more faithfully during manufacture, (3) the possibility of broader variation in their heat value (2.7–5.4 megajoules per kg, or 650–1,300 kilocalories per kg) by proportioning the mix formulation, (4) a higher powder force constant, and (5) 20–30 percent lower production cost.

The disadvantages of cordites include (1) increased deterioration of the gunbarrel bores because of the high combustion temperature; (2) reduced physical stability at low temperatures (below 7°C), resulting in the formation of nitroglycerin on the surface of the grains and making the powder dangerous to handle; and (3) greater hazards in powder manufacture because of the nitroglycerin’s high sensitivity to external influences.

Cordites can be stored safely for approximately 20 years, al-though the powder’s period of useful service may be 1.5–2 times less because of a loss of ballistic qualities.

Cordite powder elements for small arms and artillery are manufactured in a variety of shapes and sizes (tubes, plates, strips).