Indirect Fire

Indirect fire weapons include artillery units equipped with either field guns (howitzers), or heavy mortars. Artillery is that part of an army that controls the bigger, long range weapons, formerly referred to as cannons. In battle, the artillery's role is to provide fire support for the infantry, cavalry, armor and other units. The projectile, rocket, missile, and bomb are the weapons of indirect-fire systems. Indirect fire can cause casualties to troops, inhibit mobility, suppress or neutralize weapon systems, damage equipment and installations, and demoralize the enemy. Historically, more combat deaths have been caused by indirect fire weapons than by any other means, hence the designation of artillery as the King of Battle. Most casualties to troops in an indirect-fire attack are caused by the initial rounds. Best results are achieved by a short engagement at a high rate from as many weapons as possible.

The traditional tactic for artillery, as perfected by Napoleon, was to concentrate the guns in a direct-fire role, placing them between or a few hundred meters behind the infantry units they were supporting. This tradition of direct-fire support meant that by 1914 all armies had standardized on relatively light, highly maneuverable field guns with flat trajectories, even after advances in technology had made accurate indirect fire possible. The French 75-mm, the German 77-mm, the American and Russian 3-inch (76.2-mm), and the British 18-pounder (83.8-mm) were all designed for this role.

The Russo-Japanese War, provided a glimpse into the future, with the skillful use, particularly by the Japanese, of indirect-fire artillery. Observers of the Russo-Japanese War, especially those from the German Army and British Royal Artillery, were impressed with the necessity for indirect fire, if only to protect the gun crews from enemy counter-battery fire. Beginning in 1909, the Germans increased their indirect-fire capability by converting one battalion in each division to 105-mm howitzers and by adding a battalion of 150-mm howitzers to each corps artillery. These weapons had an effective range of 7.5 kilometers, as opposed to the French 75-mm with a four kilometer range.

The defensive power of indirect artillery and machine guns dominated the battlefields of 1914. Once the infantry attacks failed and trench warfare because the reality of combat, the most obvious means of creating a penetration was massed artillery fire. Many of the procedures that are commonplace to artillerymen today were developed painfully during the period 1914-1917: establishing forward observer techniques, measuring and compensating for the effects of weather and worn barrels, and using ammunition from the same production lot to ensure that successive volleys fell in the same general area.

The precision revolution progressed more slowly to indirect fire because to hit an unseen target with the first round required refinements in the ability to locate both the target and the firing position, as well as the ability to predict very accurately the ballistic course of a projectile. Ballistic refinement arrived with the development of digital fire-control computers, precise weather-measuring devices, and devices to measure the velocity of a projectile in flight. Target-acquisition radars, laser range finders, and the now indispensable GPS allowed a similar precision in locating targets and firing positions. If all of the parts are assembled and employed properly, the radius of error for a "dumb" artillery projectile is easily cut in half. DPICM or bomblet artillery munitions, in turn, have almost tripled the kill radius for artillery. This quantum jump in precision and lethality mean that for the first time in history the artillery kill radius was greater than its radius of error. In other words, if American artillery shoots at a target, it died.

The Artillery continues to increase the accuracy, lethality and range of its projectiles and missiles. The move towards smart munitions that attack specified targets instead of exploding nearby supports the Army's vision for the 21st Century. The need for mass quantities of iron rounds significantly decreases with more lethal, more accurate munitions. The artillery leads the Army in this field with cannon SADARM and the ATACMS family of missiles. These munitions diminish the need for large fleets of ships and aircraft to supply vast ammunition dumps in theater. This creates room on carriers for other vital equipment that previously waited for transportation. Artillery weapon systems continue to improve in conjunction with the new munitions. MLRS is a prime example of this improvement. The basic launcher gained international attention during the Gulf War. The artillery sought improvements in MLRS to increase response time and to accept the ATACMS family of missiles. The artillery continues to test the MLRS concept in a truck mounted version (HIMARS) for the light divisions.

Categories of Indirect Fire. Indirect fires are divided into two basic categories: observed and unobserved.

Observed fire. Observed fire is fire for which the points of impact or burst can be controlled by an observer. Seldom will there be enough indirect-fire units or ammunition available to meet all the demands for indirect-fire support. By ensuring fire is observed when accuracy cannot be guaranteed, the most effective and economical use of indirect-fire weapons is attained. Observed fire will result in target damage assessment (TDA) reports.

Unobserved fire. Unobserved fire is fire for which the points of impact or burst are not observed. It involves predicting where targets are, or will be, and placing fire on them. Use of unobserved fire requires follow-up activity to assess effectiveness.

Effects of Fire. A commander will decide what effect fire support must have on a particular target. There are three types of fire: destruction, neutralization, and suppression.

Destruction. Destruction puts a target out of action permanently. Direct hits with high-explosive (HE) or concrete-piercing (CP) shells are required to destroy hard materiel targets. Usually, destruction requires large expenditures of ammunition and is not considered economical, except for nuclear weapons.

Neutralization. Neutralization knocks a target out of action temporarily. It can be achieved by use of any type of shell-fuze combination suitable for attacking a particular type of target. Neutralization does not require an extensive expenditure of ammunition and is the most practical type of mission. Most missions are neutralization fire.

Suppression. Suppression of a target limits the ability of the enemy Personnel in the target area to perform their jobs. Firing HE/VT or smoke creates apprehension and confuses the enemy. The effect of suppressive fires usually lasts only as long as the fires are continued. Suppression requires a low expenditure of ammunition; however, since its effects are not lasting, it is unsuitable for most targets.

Nonlethal Attack Systems and Munitions Smoke, illumination, and offensive electronic warfare can exploit, disrupt, and deceive the enemy. Jammers can affect the command and control system, radars, and navigational aids by causing the enemy to receive false information. This degrades the overall effectiveness of the enemy system.

Reconnaissance by Fire Advance parties place direct fire on positions where there is a reasonable suspicion of enemy occupation; the goal is to cause the enemy to disclose his presence by movement or returning fire. Advance parties use this technique when enemy contact is expected and time is limited. Reconnaissance by fire does not work in all cases. For example, disciplined troops in prepared positions will not react to the advance party's fires.

Killer Junior This technique was developed during the Vietnam War to defend fire bases against enemy ground attack and used mechanical time-fuzed projectiles set to burst approximately 30 feet off the ground at ranges of 200 to 1,000 meters. This technique proved more effective in many instances than direct fire with Beehive ammunition because the enemy could avoid Beehive by lying prone or crawling. Another successful application of the Killer technique was in clearing snipers from around base areas. The name Killer came from the radio call sign of the battalion that perfected the technique. To speed the delivery of fire, the crew of each weapon used a firing table containing the quadrant, fuze settings, and charge appropriate for each range at which direct fire targets could be acquired. Firing a fuze setting lessthan what corresponds to a range of 650 meters is restricted to combat emergency conditions only. Firing a fuze setting less than this value results in a danger close hazard to the crew.


The field artillery system provides close support to maneuver forces, counterfire, and interdiction as required. These fires neutralize, canalize, or destroy enemy attack formations or defenses; obscure the enemy's vision or otherwise inhibit his ability to acquire and attack friendly targets; and destroy targets deep in the enemy rear with long-range rocket or missile fires. Field artillery support can range from conventional fires in a company zone to massive nuclear and chemical fires across a corps front.

Close Support Fires. These fires are used to engage enemy troops, weapons, or positions that are threatening or can threaten the force in either the attack or the defense. They allow the commander to rapidly multiply combat power effects and shift fires quickly about the battlefield. Close support expands battlefield depth, erodes enemy forces, and inflicts damage well beyond direct-fire ranges.

Counterfires. Counterfires are used to attack enemy indirect-fire systems, to include mortar, artillery, air defense, missile, and rocket systems. Observation posts and field artillery command and control facilities are also counterfire targets. Counterfire allows freedom of action to supported maneuver forces and is provided by mortars, cannons, guns, and aircraft. Within the field artillery, counterfire is normally the primary responsibility of general support (GS) and general support reinforcing (GSR) units. However, it may be fired by any unit.

Interdiction Fires. These fires are used to disrupt, delay, and destroy enemy forces that, because of range limitations or intervening terrain, cannot fire their primary weapon systems on friendly forces. Targets include first-echelon forces not participating in the direct battle and follow-on echelons. Interdiction fires create 'windows" for friendly unit offensive maneuver.

Indirect Fire in Urban Operations

Mortars, Field Artillery and Naval Gunfire are not the primary asset to support forces in a military operations in urban terrain [MOUT] environment. Indirect fires are simply not accurate enough to provide the close-in fires needed to accomplish the majority of the missions required of the maneuver. Mortars require additional planning considerations such as ammunition resupply, constructing a stable platform, maneuverability, and security. Electrical interference and structural steel found in urban environments may effect the use of the aiming circle and communications. Mortars are usually most effective when used in a blocking position or placed in an area where it can take full advantage of its high angle of fire and steep rate of fall, allowing it to impact behind buildings and other tall structures.

If collateral damage and the death of civilian non-combatants is not an issue, then Field Artillery and Naval Gunfire should be employed to their maximum lethality prior to friendly forces entering the MOUT environment. Field Artillery can be very effective when used to deliver laser guided munitions against known enemy fortifications, delay or concrete piercing fuzes also can provide excellent penetration of reinforced structures, fuze time can be adjusted and used against personnel in the streets or on rooftops.

Variable time and proximity fuze should be avoided because high structures may cause the round to detonate prematurely. Naval Gunfire can be devastating when attacking targets on a waterway or coastline, the ships' mobility and high muzzle velocity (flat trajectory) make it an excellent FS platform for this situation. Naval Gunfire can also be used similarly to FA in providing fire support against a counter-attacking force. In the embattled city of Fallujah, Iraq - the flash point of resistance to the United States and its Iraqi allies - 10,000 US Marines and soldiers were in a grim showdown with scores of holed-up militants. But the Marine and Army grunts had a Sunday punch in their corner: the 155 leathernecks of Battery M, 4th Battalion, 14th Marine Regiment, and their six massive 155 mm howitzers.

In the Battle for Fallujah, November - December 2004, all six howitzers in the 1st Marine Division Battery M, 4/14 Mmrines were up and ready to support the Marines on the ground at any time during the fight. A Marine who was pinned down 60 meters away from insurgents called in for artillery fire dangerously close to his position and latter said he knew that without artillery fire he wouldn't be alive.

Army Task Force 2nd Battalion, 2nd Infantry Regiment Paladin Howitzers were able to provide timely and accurate fires throughout the fight, delivering 925 rounds in mostly danger close fires less than 600 meters from friendly soldiers and often within 100-200 meters from friendly forces. A big lesson learned was that even when responsive, Close Air Support, is not a substitute for artillery and mortars. It can be very effective, but it is not as responsive as artillery and mortars by a longshot.

While the battle against terrorists and insurgents moved from house to house through the streets of Fallujah, Iraq, a group of U.S. soldiers on the outskirts of the city rained precise destruction down on the enemy in support of the coalition's front-line fighters. "Artillerymen of the 1st Cavalry Division's Battery A, 3rd Battalion, 82nd Field Artillery Regiment, fired roughly 1,600 rounds against enemy targets during a two-week period. Powerful artillery pieces such as the Paladin deserved much of the credit for the ease and speed with which the US military has been able to take control of most of Fallujah, according to American soldiers who have been sweeping through the city over the past two days."

Ascendancy of Fires

In the past, even when field pieces were aimed correctly, they scattered rounds in a broad dispersion pattern. Because of this, gun crews had to use vast amounts of ordnance to destroy targets. Moreover, only a direct hit would stop a tank. For example, the Fire Support Mission Area Study of 1974 indicated that an average of fifty conventional 155-mm. howitzer high-explosive rounds were required to hit a stalled tank at eight kilometers and that even a greater number of rounds would be needed to kill a moving tank.

The Ascendancy of Fires is a concept that describes the combined results of the improving ability to "see the battlefield", while simultaneously attacking at depth with precision lethality. The Ascendency of Fires describes a potential trend where land warfare is becoming more like sea and air warfare, i.e. forces will fight at increasingly greater ranges in "demassed formations." In this setting, combat elements conducting superior information operations and employing state-of-the-art smart/brilliant munitions, robotic vehicles, and swarms of unmanned aerial vehicles, can conceivably shape the battlefield and conduct decisive operations, possibly without coming in visual contact of each other. This would produce a dispersed combat situation where small, powerful, highly mobile tactical units employing precision fires, fight almost independently over incredibly large distances. The national mandate to win quickly with minimum casualties remains the driving factor in the emerging Ascendancy of Fires.

As evidenced in Iraq and Afghanistan, soldiers and Marines expect cannon artillery support when going into combat. They know they often can't survive or accomplish their mission without it. Cannon artillery is the only immediate response, 24-hour, all-weather fire support for ground forces, whether attacking Baghdad or destroying enemy positions threatening Marines in Fallujah.

The Army is reorganizing for the future, and cannon artillery is a part of each ground combat unit. Revolutionary cannon technologies like CCF will make cannon artillery more precise, mobile and lethal and will exponentially reduce the Army's logistics tail.

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