Ammunition, military stores or provisions for attack or defence. In modern usage, the signification of the term is confined to the articles which are used in charging firearms and ordnance of all kinds, as gunpowder, balls, shot, shells, percussion caps, primers, and cartridges, prepared and ready for use. Small-arm ammunition comprises cartridges and percussion caps, the latter having replaced flints, and in turn been replaced by an arrangement of the fulminate or exploding materials in the base of the metallic cartridges now coming into general use throughout the world. Field artillery ammunition is composed of shot, loaded shell, case shot, shrapnel, cartridges, priming tubes, matches, portfires, etc, with rockets for rocket batteries. In fortresses and for sieges, the powder is generally kept in barrels, and made up in cartridges when required for use; so are the various compositions required during a siege. The proportion of ammunition accompanying an army in the field varies according to circumstances. Generally an infantry or cavalry soldier carries from 40 to 60 rounds, while a similar or larger quantity per man accompanies the army in wagons, or in exceptional cases, for the use of cavalry, is carried upon pack mules.

For field artillery, from 100 to 200 rounds per gun are always kept with the battery, partly in the limber boxes, and partly in separate wagons called caissons. Another 200 rounds are generally with the ammunition reserve of the army, and a third supply follows in wagons, or is kept on hand at depots established at convenient points near the theatre of war. Ammunition for siege and seacoast guns, garrison and naval use, consists mainly of gunpowder, shot, and shell, and is supplied in large quantities proportioned to the probable requirements in each case, the usual practice in time of war being to have from 50 to 150 rounds prepared and ready for use, and the magazines stored with materials for from 600 to 1,000 rounds more. The proportional weights of gunpowder and missiles used in compounding ammunition vary considerably, and are set forth in the manuals and regulations pertaining to that branch of the military service. After a few months of active campaigning, the supplies of ammunition are generally severely drawn upon: and until the introduction of metallic cartridges for small-arms, as much was worn out and rendered useless by the troops while marching as was expended in battle.