Field artillery

Field artillery is a category of mobile artillery used to support armies in the field. These weapons are specialized for mobility, tactical proficiency, short range, long range, and extremely long range target engagement.

Until the early 20th century, field artillery were also known as foot artillery, for while the guns were pulled by beasts of burden (often horses), the gun crews would usually march on foot, thus providing fire support mainly to the infantry. This was in contrast to horse artillery, whose emphasis on speed while supporting cavalry units necessitated lighter guns and crews riding on horseback.

Whereas horse artillery has been superseded by self-propelled artillery, field artillery has survived to this day both in name and mission, albeit with motor vehicles towing the guns (this towed artillery arrangement is often called mobile artillery), carrying the crews and transporting the ammunition. Modern artillery has also advanced to rapidly deployable wheeled and tracked vehicles and precision delivered munitions capable of striking targets at ranges between 15 and 30 kilometers.^{[citation needed]}

Early artillery was unsuited to the battlefield, as the extremely massive pieces could not be moved except in areas that were already controlled by the combatant. Thus, their role was limited to such functions as breaking sieges. Following the beginning of the gunpowder era, the first field artillery came into being as metallurgy allowed thinner cannon barrels to withstand the explosive forces without bursting. However, there was still a serious risk of the constant changes of the battlefield conspiring to leave behind slow-moving artillery units – either on the advance, or more dangerously, in retreat. Artillery units were particularly vulnerable to assault by light cavalry, which were frequently used in this role. Only with a number of further inventions (such as the limber, hitched to the trail of a wheeled artillery piece equipped with trunnions), did the concept of field artillery really take off.

The medieval Ming dynasty Chinese invented mobile battlefield artillery during the early part of the fourteenth century at the time when gunpowder and the primordial cannon were first being adopted in the West. One of the earliest documented uses of field artillery is found in the 14th-century Ming Dynasty treatise Huolongjing. The text describes a Chinese cannon called a "thousand ball thunder cannon", manufactured of bronze and fastened with wheels. The book also describes another mobile form of artillery called a "barbarian attacking cannon" consisting of a cannon attached to a two-wheel carriage.

Before World War I, field artillery batteries generally fired directly at visible targets measured in distances of meters and yards. Today, modern field batteries measure targets in kilometers and miles and often do not directly engage the enemy with observed direct fire. The hundredfold increase in the range of artillery guns in the 20th century has been the result of development of rifled cannons, improvements in propellants, better communications between observer and gunner, and technical improvements in gunnery computational abilities.

Most field artillery situations require indirect fire due to weather, terrain, night-time conditions, distance, or other obstacles. These gunners can also rely upon a trained artillery observer, also called a forward observer, who sees the target and relays the coordinates of the target to their fire direction center, which in turn translates those coordinates into: a left-right aiming direction; an elevation angle; a calculated number of bags of propellant; and finally a fuze with a determined waiting time before exploding (if necessary) to be set, which is then mated to the artillery projectile now ready to be fired.

Modern field artillery (i.e. post-World War I) has three distinct sections: All batteries have a Fire Support Man (Forward Observer), Fire Direction Control (FDC), and Cannoners (Gunner).