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Chapter 1


The mission of the Field Artillery is to destroy, neutralize, or suppress the enemy by cannon, rocket, and missile fires and to help integrate all fire support assets into combined arms operations. Field artillery weapons are normally employed in masked or defilade positions to conceal them from the enemy. Placing the firing platoon in defilade precludes direct fire on most targets. Consequently, indirect fire must be used when FA weapons fire on targets that are not visible from the weapons. The gunnery problem is an indirect fire problem. Solving the problem requires weapon and ammunition settings that, when applied to the weapon and ammunition, will cause the projectile to achieve the desired effects on the target.

1-1. Gunnery Problem Solution

a. The steps in solving the gunnery problem are as follows:

(1) Know the location of the firing unit, and determine the location of the target.

(2) Determine chart (map) data (deflection, range from the weapons to the target, and altitude of the target).

(3) Determine vertical interval (VI) and site (si).

(4) Compensate for nonstandard conditions that would affect firing data (meteorological [met] procedures).

(5) Convert chart data to firing data (shell, charge, fuze, fuze setting, deflection, and quadrant elevation).

(6) Apply the firing data to the weapon and ammunition.

b. The solution to the problem provides weapon and ammunition settings that will cause the projectile to function on or at a predetermined height above the target. This is necessary so the desired effects will be achieved.

1-2. Field Artillery Gunnery Team

The coordinated efforts of the field artillery gunnery team are required to accomplish the solution of the gunnery problem outlined in paragraph 1-2. The elements of the team must be linked by an adequate communications system.

NOTE: The terms battery and platoon used throughout this manual are synonymous, unless otherwise stated.

a. Observer. The observer and/or target acquisition assets serve as the "eyes and ears" of all indirect fire systems. The mission of the forward observer is to detect and locate suitable indirect fire targets within his zone of observation and bring fires on them. When a target (tgt) is to be attacked, the observer transmits a call for fire and adjusts the fires onto the target as necessary. An observer provides surveillance data of his own fires and any other fires in his zone of observation. Field artillery observers include the following:

  • Aerial observers (AOs).
  • Forward observers (FOs).
  • Fire support teams (FISTs).
  • Combat observation/lasing teams (COLTs).
  • Air and naval gunfire liaison company (ANGLICO).
  • Firepower control teams (FCTs).
  • Any other friendly battlefield personnel.

b. Target Acquisition. Target acquisition assets also function as observers. They provide accurate and timely detection, identification, and location of ground targets, collect combat and/or target information, orient and/or cue intelligence sources, and permit immediate attack on specific areas. Field artillery target acquisition (TA) assets include the following:

  • Weapons-locating radar sections.
  • Aircraft radar systems.

NOTE: See FM 6-121 for a discussion of TA assets. See FMs 100-2-1, 100-2-2, and 100-2-3 for information on target characteristics.

c. Fire Direction Center. The fire direction center (FDC) serves as the "brains" of the gunnery team. It is the control center for the gunnery team and is part of the firing battery headquarters. The FDC personnel receive calls for fire directly from an observer or they maybe relayed through the initial fire support automated system (IFSAS) at battalion level. The FDC will then process that information by using tactical and technical fire direction procedures.

(1) Tactical fire direction includes processing calls for fire and determining appropriate method of fire, ammunition expenditure, unit(s) to fire, and time of attack. The fire direction officer's decision on how to engage the target is concisely stated as a FIRE ORDER.

(2) Technical fire direction is the process of converting weapon and ammunition characteristics (muzzle velocity, propellant temperature, and projectile weight), weapon and target locations, and met information into firing data. Firing data consist of shell (sh), charge (chg), fuze (fz), fuze setting (FS), deflection (df), and quadrant elevation (QE). The FDC transmits firing data to the guns as fire commands.

d. Firing Battery. The firing battery serves as the "muscle" of the gunnery team. The firing battery includes the battery HQ, the howitzer sections, the ammunition section, and the FDC. The howitzer sections apply the technical firing data to the weapon and ammunition. Organization and employment considerations of the firing sections are discussed in FM 6-50.

1-3. Five Requirement for Accurate Predicted Fire

To achieve accurate first-round fire for effect (FFE) on a target, an artillery unit must compensate for nonstandard conditions as completely as time and the tactical situation permit. There are five requirements for achieving accurate first-round fire for effect. These requirements are accurate target location and size, firing unit location, weapon and ammunition information, met information, and computational procedures. If these requirements are met, the firing unit will be able to deliver accurate and timely fires in support of the ground-gaining arms. If the requirements for accurate predicted fire cannot be met completely, the firing unit maybe required to use adjust-fire missions to engage targets. Adjust-fire missions can result in less effect on the target, increased ammunition expenditure, and greater possibility that the firing unit will be detected by hostile TA assets.

a. Target Location and Size. Establishing the range (rg) from the weapons to the target requires accurate and timely detection, identification, and location of ground targets. Determining their size and disposition on the ground is also necessary so that accurate firing data can be computed. Determining the appropriate time and type of attack requires that the target size (radius or other dimensions) and the direction and speed of movement be considered. Target location is determined by using the TA assets mentioned in paragraph 1-2.

b. Firing Unit Location. Accurate range and deflection from the firing unit to the target requires accurate weapon locations and that the FDC knows this location. The battalion survey section uses the position and azimuth determining system (PADS) to provide accurate survey information for the battery location. Survey techniques available to the firing battery may also help in determining the location of each weapon. The FDC can determine the grid location of each piece by using the reported direction, distance, and vertical angle for each piece from the aiming circle used to lay the battery.

c. Weapon and Ammunition Information. The actual performance of the weapon is measured by the weapon muzzle velocity (velocity with which the projectile leaves the muzzle of the tube) for a projectile-propellant combination. The firing battery can measure the achieved muzzle velocity of a weapon and correct it for nonstandard projectile weight and propellant temperature. This is done by using the M90 velocimeter and muzzle velocity correction tables (MVCT M90-2) for each type of charge and projectile family. Calibration should be conducted continuously by using the M90 velocimeter. Firing tables and technical gunnery procedures allow the unit to consider specific ammunition information (weight, fuze type, and propellant temperature); thus, accurate firing data are possible.

d. Meteorological Information. The effects of weather on the projectile in flight must be considered, and firing data must compensate for those effects. Firing tables and technical gunnery procedures allow the unit to consider specific met information (air temperature, air density, wind direction, and wind speed) in determining accurate firing data.

e. Computational Procedures. The computation of firing data must be accurate. Manual and automated techniques are designed to achieve accurate and timely delivery of fire. The balance between accuracy, speed, and the other requirements discussed in this chapter should be included in the computational procedures.

f. Nonstandard Conditions. If the five requirements for accurate predicted fire cannot be met, registrations can be conducted or a met + VE technique can be completed to compute data that will compensate for nonstandard conditions. Applying these corrections to subsequent fire missions will allow the unit to determine accurate firing data. Accuracy of these fires will be a direct function of the observer's target location.

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