1. ROLE OF FIELD ARTILLERY. Field artillery is a supporting arm. It contributes to the action of the entire force by giving close and continuous fire support to infantry (cavalry) (armored) units and by giving depth to combat by counterbattery fire, fire on hostile reserves, fire to restrict movements in rear areas, and fire to disrupt command agencies.

2. CHARACTERISTICS OF FIELD ARTILLERY.

a. General. Field artillery is an arm for relatively long range combat. Massed artillery fire possesses great power of destruction and neutralization. Artillery fire can be shifted rapidly in width and depth without changing positions. Artillery positions can be changed quickly during combat, and units can be regrouped to bring greater fire power to bear on important sectors. This flexibility gives the commander a powerful means of influencing the course of combat. The efficiency with which artillery fires are maneuvered depends upon adequate control, close liaison with supported troops, and efficient communications and observation.

b. Modes of transportation. Field artillery units differ in mobility depending on the type of transportation used.

(1) HORSE ARTILLERY. Horse artillery has great battlefield mobility. The cannoneers are individually mounted and their mounts furnish a reservoir for draft replacements and relays. It can march and maneuver with horse cavalry.

(2) PACK ARTILLERY. Pack artillery can operate over ground that is difficult or impassable for other types of artillery. It is suitable for mountain and jungle combat. Pack artillery cannot move faster than a walk, except for short distances. It marches quietly.

(3) MOTOR-DRAWN ARTILLERY. Artillery may be towed behind trucks, tractors, or other motor vehicles. Truck-drawn artillery has much greater mobility on roads than other types.

(4) SELF-PROPELLED ARTILLERY. Artillery may be mounted in wheeled, half-track, or full-track vehicles. Such artillery can move more rapidly into and out of position than towed artillery.

(5) AIRBORNE ARTILLERY. Artillery and its ground transportation may be carried in aircraft. Some types of artillery may be dropped by parachute.

c. Capabilities of weapons. Artillery is classified, based on caliber and weight, as light, medium, and heavy. All three classifications may include mortars, howitzers, and guns.

(1) Light artillery includes the 105-mm howitzer and smaller cannon. Its characteristics are mobility, flexibility of fire, high rate of fire, and rapidity of getting in and out of position. These characteristics, coupled with its range, enable it to render continuous support to other ground forces over areas of great width and depth.

(2) Medium artillery varies from the 4.5-inch gun to the 155-mm howitzer, both inclusive. Medium artillery has a lower rate of fire but greater power than light artillery. Its weight of projectile and range make it preferable to light artillery for counterbattery. Its mobility over difficult terrain is appreciably less than that of light artillery.

(3) Heavy artillery includes the 155-mm gun and those of heavier caliber. Heavy artillery has a relatively low rate of fire, great power, and long range. It can execute counterbattery and interdiction deep within the enemy lines and can intensify and extend the neutralizing fires of light and medium artillery. It requires appreciably more time for emplacement than light and medium artillery.

3. HOWITZER (GUN) BATTERY (FM 6-101). The howitzer (gun) battery is the basic field artillery unit; it is the smallest unit containing the personnel and equipment necessary for maneuver, delivery of fire, maintenance, and administration.

4. HOWITZER (GUN) BATTALION (FM 6-101). The howitzer (gun) battalion consists of a headquarters, two or more howitzer (gun) batteries (usually three), and a service unit. It has both tactical and administrative functions. The battalion is the usual unit for executing fire missions.

5. OBSERVATION BATTALION (FM 6-120). The observation battalion is equipped to execute flash and sound ranging and to furnish topographic service and meteorological data.

6. GROUP (FM 6-100). A group consists of any combination of artillery units, usually from two to four battalions. A group headquarters is designated. It may be the headquarters of one of the units forming the group, or it may be a group headquarters (T/O 6-12).

7. DIVISION ARTILLERY (FM 6-100). The division artillery consists of a division artillery headquarters, headquarters battery, and such artillery battalions as are organic or attached. The artillery organically assigned to a division is the minimum habitually required for combat. For any action, except against weak forces, additional artillery is necessary.

8. BRIGADE (FM 6-100). The brigade consists of a brigade headquarters, headquarters battery, and such groups and battalions as are attached. Its functions are primarily tactical.

9. CORPS ARTILLERY (FM 6-100). The corps artillery consists organically of a corps artillery headquarters and headquarters battery and an observation battalion. Artillery brigade and group headquarters, groups, and battalions are attached as necessary. The term "artillery with the corps" includes both corps and division artillery.

10. ARMY ARTILLERY. There is no organic army artillery. The general headquarters or theater commander allocates artillery to an army for specific operations.

11. GENERAL HEADQUARTERS ARTILLERY. General headquarters artillery includes all artillery not organic to corps and divisions.

12. GENERAL. Artillery fire may be classified as to types of ammunition employed, effect sought, form, whether observed or unobserved, and degree of prearrangement.

13. AMMUNITION. Artillery projectiles may be solid, or filled with high explosive or chemicals. Chemical shells may contain persistent gas, non-persistent gas, or smoke. Fuzes are classified as time or impact. Impact fuzes may be quick or delay.

14. EFFECT SOUGHT. Artillery fire may be for neutralization, destruction, registration, harassing, or interdiction effect.

a. Neutralization. Fire delivered on areas to destroy the combat efficiency of enemy personnel by causing severe losses and interrupting movement or action. Neutralization is established by delivering surprise fire in intense masses. It is maintained by intermittent bursts of fire in lesser amounts.

b. Destruction. Fire delivered for the sole purpose of destroying material objects. It requires, except when direct laying is used, a great deal of ammunition and time. Observation is essential. For the destruction of most targets, medium and heavy artillery are better suited than is light artillery. Fire is generally by one gun.

c. Registration. Fire delivered to obtain corrections for increasing the accuracy of subsequent fires.

d. Harassing. Fire delivered during relatively quiet periods, to lower enemy combat efficiency by keeping his troops unnecessarily alerted. Fire may be by single piece, platoon, or battery; the fire is intermittent. All echelons of artillery may fire harassing fire.

e. Interdiction. Fire delivered on points or areas to prevent the enemy from using them. Characteristic targets are roads used for moving supplies or reserves, crossroads, assembly areas, railroad stations, detraining points, defiles, bridges, and fords.

15. FORM. Artillery fires are classified as to form as concentration or barrage.

a. Concentration. A concentration is a volume of fire placed on an area within a limited time. The term is applied regardless of the tactical purpose of the fire or the nature of the tactical operation.

b. Barrage. A barrage is a special type of prearranged fire placed on a line either stationary or moving. Barrages are fired close in front of our own front lines.

(1) STANDING BARRAGE. Standing barrage is fire on a fixed line.

(2) NORMAL BARRAGE. Normal barrage is a standing barrage placed on a critical area that cannot be covered effectively by the weapons of the supported troops. A battery has only one normal barrage. It is laid on its normal barrage when not otherwise engaged, and fires the barrage on signal or call from the supported unit.

(3) EMERGENCY BARRAGE. An emergency barrage is a standing barrage employed to cover gaps between normal barrages or to reinforce the normal barrage of another unit. A battery may have any number of emergency barrages. Such barrages are usually fired on call rather than signal.

(4) ROLLING BARRAGE. A rolling barrage is artillery fire delivered on one or more successive lines, advancing according to a prearranged schedule. Rolling barrages are employed to support an attack when the locations of hostile dispositions are obscure; to crater the ground; or to orient and guide the attacking troops.

(5) BOX BARRAGE. A box barrage is a special type of standing barrage inclosing two or more sides of an area. It is employed to isolate a portion of the hostile front.

(6) The authorized rate of fire and the effective width of burst limit the width of a barrage which may be effectively covered by a battery. The following widths of barrages per battery of four pieces should not be exceeded.

	75-mm   105-mm   155-mm   Normal barrage   200 yards   300 yards   400 yards   Emergency barrage   200 yards   300 yards   400 yards   Rolling barrage   100 yards   200 yards   *See note.
	*Not suitable for firing close to our troops. May be used to add depth to barrage.

16. OBSERVED OR UNOBSERVED. Adjusting and correcting artillery fires by direct observation increases the effectiveness of artillery. Fires may be delivered on unobserved targets when the relative location of such targets with respect to the unit firing can be determined. (See FM 6-40 for detailed description of firing methods.)

17. DEGREE OF PREARRANGEMENT.

a. Prearranged fires. Fires planned in advance. They may be prearranged as to location and time of firing, for example, as part of a preparation; or they may be prearranged as to location only and then fired on call, for example, as a normal barrage.

b. Targets of opportunity. Targets for which fires are not prearranged. If an observer reports such a target while the unit is firing a prearranged mission, the artillery commander who receives the report decides whether to continue the current firing or to attack the new target.

18. MAPS. Unobserved fires require that either a fire control map, a photomap, or coverage by vertical air photographs of target and gun position be available.

19. GENERAL. Artillery assigned or attached to a unit may be retained by that unit or attached to a lower unit. Control of artillery units is decentralized when the artillery commander cannot effectively exercise control of their operations. Artillery may be given either the mission of direct support or general support. A unit employed in general support may be given a secondary mission of reinforcing the fires of another artillery unit.

20. DIRECT-SUPPORT MISSION. Direct-support artillery has the mission of supporting a subordinate unit of a command. Whenever practicable, a particular artillery unit is placed in direct support of the same unit. Fire missions of a unit in direct support usually come directly from the supported unit. Direct-support artillery is not attached to the supported unit, but remains under the control of the higher artillery commander. The commander of a unit in direct support is free to maneuver as necessary, in order to furnish maximum aid to the supported unit. In the division (corps), fire of a unit in direct support may not be taken from the supported unit except with the authority of the division (corps) commander.

21. GENERAL-SUPPORT MISSION. General-support artillery has the mission of supporting the command as a whole. It is held under the control of the artillery commander. It is an immediate reserve available to the force commander with which he can influence the action.

22. REINFORCING MISSION. An artillery unit with a reinforcing mission receives calls for fire directly from the unit whose fires it is to reinforce. The reinforcing unit must be prepared to fire in the zone of the reinforced unit, to answer all calls for fire from the reinforced unit when answering such calls will not interfere with its primary mission, and to maintain liaison with the unit whose fires it is to reinforce.

23. ARTILLERY IN RESERVE. Artillery should not be held in reserve unless the situation is so obscure that the particular sector in which the bulk of the artillery fire power will be most needed cannot be foreseen. Artillery in support of a unit held in force reserve should be placed in general support of the force, if time will permit its employment with the reserve unit when that unit is committed.

24. TACTICAL ORGANIZATION.

a. The artillery of a command is organized for combat by attaching units where necessary and by assigning missions to the subordinate artillery units. In the division, organization for combat should provide artillery in direct support and artillery in general support. In the corps, organization for combat should provide for reinforcing the fires of division artillery and artillery to execute counterbattery, harassing, and interdiction fires.

b. To simplify control, various artillery units may be grouped. The artillery commander's order specifies the commander and headquarters of the group, the units that are to compose it, and its mission. The purpose of forming a group is to coordinate fire, observation, and liaison; the guiding principle in forming a group is that all artillery units in it have a common mission, regardless of caliber or other characteristics. The group commander has tactical control of the unit, and is responsible for ammunition supply. If a group is formed to furnish direct support to a given unit, the commander of the organic battalion normally charged with direct support of that unit should command the group.

25. ZONES OF FIRE.

a. When unusually large numbers of artillery battalions are available, missions may be clarified and tactical organization improved by assigning zones of fire. The zone of fire of an artillery unit is the zone into which it must be prepared to fire. The normal zone of direct-support artillery coincides laterally with the zone or sector of the supported unit. Those portions of its zone of fire outside the normal zone are called contingent zones.

b. The normal zone of general support or corps artillery is either the zone or sector of the supported unit, or so much of the zone or sector as is specified. Contingent zones, into which these units may be ordered to shift their fires, may be prescribed. Commanders have primary responsibility for observation in, and ordinarily fire in their normal zones on their own initiative. Units deliver fire in their contingent zones only on order of higher artillery headquarters.

c. To insure proper coverage laterally, the exterior limits of the contingent zones of the various units are designated by lines labeled to show the fire power—usually expressed in battalions, calibers, and types—with which the units must reach the exterior limits.

d. Zones in depth may be prescribed by assigning position areas, or by prescribing minimum range lines and lines to be reached by all or part of the fire power of a unit.

26. ARTILLERY OFFICERS. The term "artillery officer" is used to designate the senior officer in the field artillery section of army and higher headquarters. In the corps and division he is the artillery commander. The army artillery officer exercises no tactical command. The artillery commander of the corps and division has a dual role. He commands all the artillery, both organic and attached, which has not been attached to subordinate units; he is a member of the special staff of his commander, in which capacity he is the assistant and adviser regarding all artillery matters. In a task force of mixed arms, the senior artillery officer is the artillery officer of the force and performs duties similar to those of the artillery officer of the unit (army, corps, or division) which the force most resembles. For detailed description of duties and functions of artillery officers, see FM 6-100.

27. CHAIN OF COMMAND. There is no direct chain of artillery command from armies to corps or from corps to divisions. An army artillery officer's instructions for the artillery with a corps are issued to the corps commander in the name of the army commander. The corps artillery commander's instructions for division artillery are transmitted similarly.

28. ARTILLERY STAFFS. The staffs of all artillery echelons are similar in organization but vary in size and in the number, magnitude, and complexity of their functions. Artillery staffs usually include special staff officers, such as communication officer, liaison officer, ammunition train commander, motor officer, surgeon, and chaplain. For general description of staff functions see FM 101-5; for details of staff functions see FM 6-100 and 6-101.

29. COMMAND POSTS. The command post of the division artillery is at the division command post. The same principle applies in the case of the senior artillery commander of any force of combined arms. This may necessitate establishing the fire direction center well forward of the command post. Separating the command post and the fire direction center does not allow the artillery commander to exercise proper control over his staff and subordinate units. Force commanders must consider this when locating their command posts. Subordinate artillery commanders establish their command posts where they can exercise tactical command and fire direction most effectively. If an artillery commander locates his command post at a place other than the command post of the supported unit, he establishes liaison and maintains signal communications with the commander of the supported unit.

30. ARTILLERY PLANS.

a. General. The basic decision as to the employment of the artillery in any operation is the responsibility of the force commander. He indicates the area in which the artillery will place the bulk of fire, or the element of the command that is to receive priority of artillery support. The artillery officer must be prepared to submit recommendations as to the employment of the artillery before the force commander formulates his decision.

b. Estimate of artillery situation and requirements. The artillery officer can be prepared properly to submit recommendations only if he and his staff have made a continuous estimate of the situation, from the artillery viewpoint, at the same time that the force commander has been making his estimate of the situation. Artillery officers of the division, corps, army, or higher echelons may be called on to estimate requirements in artillery for a projected operation. The artillery officer of the echelon ordering or conducting the operation is primarily responsible for making the estimate of artillery requirements.

c. Formulation of artillery plan. The artillery plan must provide for maximum support of the scheme of maneuver. The successive steps in the formulation of the artillery officer's plan for the employment of the artillery are—

(1) An estimate by the field artillery officer and his staff prior to the commander's decision.

(2) Submission of recommendations by the artillery officer to the commander, prior to the commander's decision.

(3) Receipt of the commander's decision.

(4) Formulation of the plan for the employment of the artillery based on the commander's decision.

(5) Preparation of the order or annex to put the plan into effect.

31. ARTILLERY ORDERS.

a. General. For a general discussion of combat orders and annexes see FM 101-5. For detailed discussions of orders of artillery units see FM 6-100 and 6-101.

b. Artillery subparagraph. The artillery subparagraph of the corps (division) field order gives the commander's decision on the employment of the artillery with the corps (division). It includes only details necessary for the information of the commanders of major echelons and for coordinating the fires of artillery units.

c. Artillery orders. Artillery orders, in general, follow the five-paragraph form. They may be fragmentary or complete, oral, written, or dictated. Artillery orders are usually oral, or in fragmentary message or overlay form, particularly in lower units. When written, they may be published as an artillery field order by an artillery commander; or as artillery annexes to the force commander's field order, in corps, divisions, and similar units.