Military Historical Library

"The War in Korea 1950-1953"

Chief Editor N. L. Volkovskiy
Editor I. V. Petrova
OOO Izdatel'stvo Poligon, Saint Petersburg 2000; 928 pp.
ISBN 5-89173-113-4

((pp. 371-390))

Chapter 8. The Use of Artillery

2. Artillery of the American and South Korean Forces

Combat use of artillery in the offensive. American artillery took part in combat operations in Korea, organized at the divisional level (also in the South Korean Army as well) and also as part of the reserve of the high command, the numbers of which grew from 10 battalions of field and antiaircraft artillery to 53 battalions. This amount of artillery permitted the allocation of 8- 10 battalions of field artillery and at least 2 battalions of antiaircraft artillery to provide support to combat operations of each American infantry division (in concert with their organic assets).

In the offense artillery was allocated the following missions: support for infantry and tanks, suppression and destruction of firing points and elimination of defensive fortifications, counterbattery and countermortar fire, prevention of transfer and concentration of reserves, disruption of command and control and operations by rear services. The last two missions were for the most part carried out by aviation. The density of artillery on the breakthrough sectors where troops were making the main effort and concentrated the bulk of the artillery force grouping reached 100 and more tubes and mortars per kilometer of front. On the secondary axes this density was 50-80 guns and mortars per kilometer of front.

The offensive normally was proceeded by an artillery and aviation preparatory bombardment. Infantry division and reserve of the high command antiaircraft artillery participated in the artillery preparation and counterbattery effort, along with self- propelled artillery and tanks. In the coastal regions ground forces offensives were also supported by naval artillery bombardment. The duration of the artillery preparation varied from 40-60 minutes to up to three days. The artillery preparation normally began at dawn. When the bombardment lasted 40-60 minutes, fire missions usually lasted 25-30 minutes each.

During artillery preparation of the KPA and CPV force defenses, their defenses were normally engaged to a depth of 7 kilometers. In this the light artillery and mortars would fire to a depth of 2-3 kilometers; heavier caliber artillery fired into the 4-7 kilometer zone, as well as massed air strikes. In the intervals between fire missions, aviation would bomb and use assault attacks on the forward edge of the defense. It as common for the artillery to shift its fires back to the forward edge of the defense as it was felt it could inflict more damage on the KPA and CPV troops.

During an offensive against a prepared defense, when it was necessary to shatter the engineer fortifications, the duration of the artillery preparation could last up to three days. In these cases the artillery weapons used included 81mm and 106.7mm mortars, all calibers of field artillery, and even 90mm and 120mm antiaircraft guns. In order to suppress enemy fire support assets located in pillboxes, bunkers and tunnels, or to destroy these fortifications, the American command frequently turned to the use of aviation.

Ignoring the significant duration and large expenditure of ammunition, artillery preparation was not always reasonably effective.

During the course of offensive combat, if the movement of the forces of the first echelon was stopped, then the artillery preparation would begin again for another 30 minutes or more. If the second artillery bombardment did not provide the desired results, a careful suppression of the defense lasting several hours or even days would begin. For this goal, a significant amount of aviation would be dedicated along with the artillery and mortars.

Divisional artillery fired on targets (objectives) along the forward edge of the defense and KPA and CPV positions in the near depths; in this a great deal of attention was paid to roads, heights, and settlements. In order to find KPA and CPV forces hiding under cover, incendiary ammunition was used. During the course of the battle and especially during the fourth stage of the war smoke projectiles and mortar bombs were also used.

Corps artillery was mainly used to suppress and destroy targets in the depths of the KPA and CPV unit deployments. The primary targets and objectives here were second echelon forces, the reserves, artillery, command and observation posts, and targets located on mountain slopes and in defilade.

The advancing infantry and tanks were supported, as is correct, by the subsequent concentration of artillery fire on individual targets or groups of targets. After the tanks and infantry had moved 2-3 kilometers into the depth of the defenses light artillery redeployed forward, but the heavier artillery only made frequent changes of position when the infantry and tanks had gone 4-5 kilometers deep (redeployment was carried out by battery or by battalion.)

An offensive with limited goals, as is correct, proposed the use of an artillery preparation of only 30-60 minutes, and on occasion up to several hours. A significant amount of artillery was allocated for this preparation. For example, during a battle for a nameless height in the Kimkori area in October 1952 the Americans allocated 17 artillery battalions. Here is another example. When preparing for the offensive of an infantry company to seize one of the heights west of Choron, American forces fired their artillery continuously over the course of 11 days to flatten the engineer works and wipe out the defenders' firing positions. During this period of time, aviation was also quite active. On the day of the offensive the artillery and aviation preparation lasted a total of 5 hours, but due to the excellent organization of the defense by the KPA and CPV forces the offensive did not meet with success.

Firing positions for artillery in the offensive were normally selected 3.1-4.7 kilometers ((e.g. 2-3 miles)) behind the forward edge of own forces (figure 13) but heavy infantry mortars and independent mortar battalions deployed 1-2 kilometers behind the lines. Prior to the start of the offensive a reserve of 500-700 rounds per weapon was created forward.

During the period of offensive combat operations there were places where control of the artillery would be centralized and decentralized. Centralized control was used when making the breakthrough of the defense at a divisional and corps level scale. During the pursuit, when the artillery was completely attached directly to the infantry units and subunits, control of the artillery was decentralized. For example, after the naval landing in the Inchon area took place nearly all of the artillery other than heavy artillery was attached to infantry units. But at the same time, when the offensive by American forces was halted and required the conduct of artillery preparations, fire control was again centralized.

The cooperation between artillery and infantry and tanks, as has already been noted, was organized by infantry unit and subunits commanders. In order to organize cooperation with infantry (tanks) the battalion commander would personally meet with the infantry regiment commander (tank subunit). In combat, artillery cooperation with tanks was frequently established via the infantry regiment commander. The tank group commander advised the infantry regiment commander of the disposition of antitank assets and other targets which interfered with the movement of the tanks. The forward observer would call for fire and provide fire adjustment. On occasion the forward observer would conduct reconnaissance against the enemy and correct fire for his guns from one of the tanks.

Combat use of artillery in the defense. During the course of defensive operations it was proposed to concentrate the main artillery force grouping along the most important axes. Field artillery battalions from the reserve of the high command, as is correct, were allocated to army corps and designated for use in creating artillery groups. The structure of an artillery group varied. For example, on 1 January 1953 the I and X US Corps each had an artillery group consisting of 4 battalions, IX US Corps had one of 6 battalions. Subordinate to the 8th US Army was the 5th Field Artillery Group consisting of 4 battalions.

Independent 106.7mm heavy mortar battalions were attached to infantry divisions. On occasion the American heavy mortar battalions were attached to South Korean divisions or the English Brigade.

Normally the organic division 105mm howitzer battalions provided immediate support to the infantry regiments. Normally each infantry battalion was supported by one battalion, and an infantry battalion by one battery. Up until the moment that it entered into combat the second echelon regiment (battalion) had its artillery battalion used to provide support to the regiments (battalions) of the first echelon. For general support, each division had a battalion of 155mm howitzers.

On occasion infantry divisions operating on the most important axes received 3-4 battalions of reinforcing artillery from the reserve of the high command. In these cases general support fires for the divisions were provided via the creation of a field artillery group of 3-4 battalions.

The infantry regiment heavy mortar companies and independent heavy mortar battalions operated together with the artillery battalions, providing immediate support to their regiments. The heavy mortars augmented the 105mm howitzer fires when suppressing enemy troops and fire support assets deployed along the forward edge of the defenses of KPA and CPV units, especially on the reverse slopes of the heights.

During the course of combat operations in Korea the Americans paid a great deal of attention to the use of heavy mortars as they considered them as an effective means of immediate fire support to the infantry.

The Americans made use of tanks in the defense to reinforce their artillery fires, and paid a great deal of attention to conducting fires from tanks using concealed firing positions. Tank fires were corrected by forward observers and by the main method of using aerial observers.

Artillery used in the defense selected primary and alternate firing positions, the distances behind the forward edge of the defense which varied from 4.5 to 6 kilometers for 105mm howitzer battalions and 7-8 kilometers for 155mm howitzer battalions (see figure 14). The artillery weapons took up firing positions along roads or immediately on the roads in prepared bunkered positions. The immediate firing positions also had dugouts for storing projectiles and foxholes for the crew. Weapons firing positions frequently had the guns deployed either in line abreast or echelon left (right). Under conditions of irregular terrain the places and deployment configuration of weapons would change (see figure 15).

Heavy mortar firing positions were selected for the most part on the reverse slope of heights at a distance of 1-2 kilometers from the forward edge of own troops. The infantry regiment heavy mortar companies and independent heavy mortar battalions took up platoon positions (with up to 4 mortars in each). The mortars were deployed in line abreast with 30-35 meters between each tube. This is why, since the firing positions for heavy mortar subunits were selected not far from the forward edge of own troops, these units suffered heavy casualties. Thus, during the defense of the Unsan area in November 1950 the 2nd Independent Heavy Mortar Battalion lost around 1/3 of its personnel and mortars. For the period between the end of November 1950 and January 1951 this same battalion lost 50% of its personnel and mortars. Similar losses were suffered by the infantry regiment heavy mortar companies.

Artillery units and subunits had the task of preparing their own positions and all- around defense. As the Americans themselves noted, the necessity of an all-around defense of the firing positions was called for by the fact that small groups of KPA and CPV troops would frequently penetrate into the rear areas and inflict considerable losses upon the artillery. For the immediate defense of the firing positions the artillery used all types of weapons found in the division (see figure 16).

The primary method of conducting artillery fire in the defense was the fire mission. Fire missions against targets (objectives) were simultaneously carried out by from one to three battalions. It was rare that only a single battery would carry out a fire mission. Normally the fire missions lasted from 3-8 minutes and expended 80-120 rounds, and could be repeated 2-3 times against the same target.

The first to open fire on advancing KPA and CPV units would be the heavy artillery. Next, when the advancing forces were 1-2 kilometers from the forward line of the defense, barrage fire would be.opened using tanks, mortars, and all artillery weapons. Fire was conducted for long periods. For example, when repulsing an attack by KPA units when forcing a crossing of the Naktong River (near Taegu) a six-howitzer 105mm battery from the 1~ Cavalry Division fired 1,820 rounds in one day (303 rounds per weapon).

When repulsing a night attack by KPA and CPV units artillery fired barrage fire. The call for fire and target designation was carried out using flares and tracer bullets. Sudden fire missions were widely used by artillery against probable areas of KPA and CPV troop concentrations, especially at night. Counterattacks by American units were supported by massive artillery fires and air strikes.

The American forces did not possess special antitank artillery units for combating KPA and CPV tanks. Therefore in order to combat tanks infantry divisions and regiments organized platoons (sections) in their regiments (battalions) armed with recoilless rifles; infantry subunits were equipped with bazookas. For immediate reinforcement of the antitank defenses in infantry subunits, the main method used was the tank company of the infantry regiment. During withdrawals during the most stressful period of combat operations, 105mm howitzers were also used to combat tanks.

The 60mm bazooka and 57mm recoilless rifle were considered to be ineffective in combating KPA and CPV tanks due to their small caliber, short range, slow velocity, and insufficient penetration capability. With that in mind in July 1950 the Americans immediately sent 88.9mm bazookas to Korea, and in early 1951 they additionally sent 105mm recoilless rifles mounted on Willys Jeeps.

The 88.9mm bazooka was first allocated as the primary weapon of the infantry, and later to other arms of service. To make better use of its new bazooka, the Americans created "tank hunter groups." Soldiers with these weapons frequently took up positions along with riflemen (machine gunners) and were part of the forward units. Together with the use of these bazookas, rifles and small arms were then used to eliminate the infantry using the tanks as cover to move forward. The shortcomings of the 88.9mm bazooka were these: short effective range against tanks (less than 200 meters), great dispersion of its rocket projectile when fired, high arcing trajectory, and insufficient rate of fire (3-4 rounds per minute) as well as immediate demasking of its position when fired. The corresponding shortcomings of the 105mm recoilless rifle mounted on the truck were its arge size, difficulty in being camouflaged, limitations on having to use roads, and vulnerability to small arms fire.

The American command paid a great deal of attention to the counterbattery fight, and they allocated 155mm guns and 203mm howitzers for this function. In order to suppress one battery of artillery it required, as is correct, an artillery battalion to expend 150- 160 rounds per hectare of suppressed area. There were cases when in order to suppress one battery of artillery it took the allocation of two battalions of artillery and an expenditure of 1,200 rounds. For suppressing mortars (a four-tube battery) it required an expenditure of 80- 100 rounds.

The counterbattery fight by American artillery was conducted for the most part via the use of aerial spotters and occasionally helicopters. In level areas of the front sound ranging was used, but on the other hand accuracy in these cases was not high. The coordinates of the firing battery could not accurately be determined, and the first sheaf of rounds often landed 500-1000 meters from their target.

In the defense, American artillery expended a great deal of ammunition. For example, in the period from 11 to 20 August 1952 over the entire front artillery fired a total of more than 300,000 rounds of various calibers; the average daily expenditure jumped from 15,000 to 40,000 rounds per day. A similar expenditure took place between 11 and 20 February 1953, when 328,000 rounds were fired with an average daily expenditure of nearly 45,000 rounds.

It required the allocation of all division artillery to repulse advancing KPA forces. Part of the artillery, to include the 155mm howitzers, was allocated for direct fire against tanks, troops and fire support means. Artillery was allocated for direct fire missions during the first three stages of the war.

Artillery fire control during the first stage of the war was decentralized. This was called for due to the conduct of combat operations across a broad front and a great distance between staffs and their units. Divisional staffs, and the divisional artillery staff collocated with them, were 45-60 kilometers from the forward units and subunits. Thus, on 6 July 1950 the 24th Infantry Division was fighting in the Chonan area but its artillery staff was located in Taejon (60 kilometers away). On 17 July 1950 combat operations moved to the Taejon area but on that date the artillery staff was then located in Yendon (45 kilometers away). At those distances it was practically impossible for the staff to control the artillery.

During the first stage of the war in most cases the artillery was not deployed and could not provide essential support to retreating forces. Moreover, during the retreat the artillery, as is correct, withdrew in the first section, and subsequently its forces were frequently left without artillery cover. With the slightest threat was made by KPA forces to the flanks or the rear area the American forces would move their artillery out of its firing positions and immediately head for the rear area. There were no reliable communications, and correspondingly no cooperation between infantry and artillery at that time. There were instances when due to the poor command and control of the artillery, and the shortcomings in their communications, the American artillery would fire upon their own forces. After August-September 1950, the command and control of artillery in the divisions was improved.

In the fourth stage of the war, when the front had stabilized, command and control of the artillery was more decentralized and achieved a reasonable level of flexibility. Artillery unit and subunit commanders controlled artillery fires from battery and battalion command posts, and at the division level from the divisional artillery fire control post.

Each battalion required a group of 10 personnel to control its fires: 2 officer- operators, 1 operator (sergeant), 1 senior calculator, 3 calculators and 3 communicators. This group allocated targets among the batteries and prepared initial firing data. Beside that, the battalion had 9 forward observers who were situated at the forward observation posts and carried out reconnaissance of the enemy and observations of shell explosions of their own artillery. The forward observers were selected from experienced artillery officers -- reconnaissance platoon leaders and firing platoon leaders, who were well acquainted with the tactics and methods of artillery fire control, as well as the tactics of operations by the supported forces and the enemy. The results of their observations were sent to the fire control post, who determined the corrections to firing data and prepared initial data for conducting fire against newly acquired targets.

If the forward observers could not adjust artillery fires, then they called for aerial observers.

The command to open fire went directly from the battalion fire control post to the batteries, as is correct, via telephone. The battery commanders sent the commands to the firing positions via radio, for which each weapon had a repeater.

In those cases when the battalion fire control post was knocked out, battalion fire control was carried out by the fire control post of one of its batteries. It follows to stress that in American Army artillery practice these battery fire control posts were set up first. Control by these posts normally only went on in artillery groups.

Artillery fire was normally called for by the infantry via a forward observer and signals officers from the artillery. For rapid and timely commencement of fire, batteries and battalions were pre-registered on reference points in the zones of the supported units and formations (a minimum of three points per zone) from which fire could be shifted onto the target. Pre-registration was carried out with the aid of aerial observers and upon observation of shell splash. Pre-registration was carried out with flash projectiles during daylight, and at night with special incendiary rounds that would leave burning embers for 3-5 minutes after detonation.

Artillery instrumental reconnaissance was carried out by mortar locating platoons (sections) and from artillery instrumental reconnaissance battalions.

In infantry regiments, the conduct of reconnaissance against enemy mortars was carried out by one mortar locating section, and each battalion of 105mm howitzers assigned to an infantry division also had a mortar locating section for this purpose. Beside that each battalion of 105mm howitzers had an instrumental-topographic section to carry out topographic locating data for the firing positions.

Artillery instrumental reconnaissance battalions were designed to determine the coordinates of enemy artillery firing positions, provide support for pre-registration and fire correction for friendly artillery, collect reconnaissance data and provide it to the relevant staffs and commanders, coordinate all operations in regard to topographic support for artillery fire on a corps level, identify the types of weapons used by friendly artillery, and provide their own subunits with meteorological data. Artillery instrumental reconnaissance battalions, as is correct, were under centralized control on behalf of the use of corps artillery. On occasion, when due to a reasonably broad front and large number of battalions included as corps artillery, control of the artillery instrumental reconnaissance battalions was decentralized and artillery instrumental reconnaissance batteries were attached to formations and units.

Use of antiaircraft artillery for covering troops. Antiaircraft batteries of the organic automatic antiaircraft battalion of infantry divisions, as a consequence of a lack of threat from KPA aviation assets, were for the most part assigned to infantry regiments by batteries and given the primary task of reinforcing their firepower against ground targets.

The antiaircraft artillery battalions of the reserve of the high commander were assigned to divisions. On occasion antiaircraft battalions from the reserve of the high command were combined into antiaircraft artillery groups of 2-4 battalions of 90mm and 120mm antiaircraft guns. Some divisions received an antiaircraft artillery group as a method of artillery reinforcement.

In the offense antiaircraft artillery, attached to regiments and divisions, was tasked with the immediate support of the infantry; support to tanks by suppressing antitank defenses, enemy fire support means, and the destruction of road obstacles; cover for the forces in movement; using self-propelled mounts to patrol along the main supply lines (together with tanks and without tanks) with a goal of repulsing attacks by partisans; and conducting the counter-mortar and counter-battery fight.

For the most effective support to ground forces and the best organization for cooperation, antiaircraft artillery was included in the formation of temporary tactical groups. Normally an infantry regiment had one antiaircraft battery attached to it.

Antiaircraft subunits were also included as part of reconnaissance groups - one antiaircraft cannon and one antiaircraft machine gun self-propelled mounts. The 90mm and 120mm antiaircraft battalions could fire at ranges exceeding those of field artillery and reach ranges of up to 17 kilometers.

The self-propelled antiaircraft mounts were used for direct fire on targets located along the forward edge or in the near depth of the defense of KPA and CPV units. Fire was carried out at ranges of 500-600 meters and was particularly effective against those targets located on hills.

When firing on troops and exposed enemy firing points the most effective fire came from the 12.7mm quadruple antiaircraft machine gun mount.

When combined in the use of antiaircraft artillery, the antiaircraft cannon mounts were deployed in the center of the position and the antiaircraft machine gun mounts on the flanks. The interval between mounts was 25-30 meters.

Antiaircraft artillery (especially self-propelled antiaircraft mounts) was used for covering troops against attacks by KPA and CPV units when they were changing positions. In these cases the antiaircraft mounts were included as part of the advance guards and moved in front of the infantry and tanks. Due to their poor armor protection they took heavy losses from enemy antitank fire. Ultimately tanks were used to move in front of the column, and the antiaircraft mounts moved behind the tanks, where they were still able to carry out their mission of suppressing antitank and other fire support means. Antiaircraft mounts also moved at the rear of the column, covering its rear.

Antiaircraft mounts were also used to reinforce the defensive positions of field artillery from attacks by ground forces.

Types of artillery ammunition. In Korea for the most part the American artillery used the same munitions that they had used during the Second World War (high- explosive fragmentation, high-explosive, cumulative, armor-piercing, flash, smoke, incendiary and illumination projectiles). New types of ammunition were the cumulative antitank round for the 90mm tank gun and the cumulative projectile for the 88.9mm bazooka.

In the offensive, battalions of l05mm and 155mm howitzers normally were supplied with 4,000 rounds of ammunition, 50% of which was kept at the firing batteries and 50% with the service battery. Out of the overall number of rounds held by battalions, the breakdown was as follows: high-explosive fragmentation with various types of fuses, including radio fuses, 75-80%; and 20-25% armor-piercing, incendiary, smoke and illumination.

Under conditions of a stable front the amount of ammunition in the firing positions was increased. The reserve firing positions, as is correct, also contained a set amount of ammunition.

Ammunition in the American forces came from the USA. Ammunition was carried from the ports by train and truck to the forward combat supply positions that were organized in the rear area of an army corps 8-30 kilometers from the front lines. Ammunition was moved from the forward combat supply positions to the firing positions by the artillery battalions' own transport.

Brief conclusions. During the course of combat operations by American forces in Korea, and ignoring the massive use of aviation, artillery fire was considered to be the primary means of supporting infantry and tanks both in the offense and in the defense. The combat use of artillery did not undergo any significant changes in accordance with this type of war in regard to the organization of artillery units and subunits, as well as the tactics and command and control of artillery. Together with that artillery had its place in combat operations and several peculiarities. First of all artillery fire in the offense was directed against the objective of the attack up until its complete destruction when artillery ammunition expenditure was not restricted. Combat against artillery and mortar batteries, as is correct, was carried out until they were totally destroyed.

In the defense tanks were used to reinforce artillery, firing both in direct fire mode and from concealed firing positions.

American forces, beside their organic artillery means, had a great deal of artillery from the reserve of the high command (38 field artillery battalions, 15 antiaircraft artillery battalions, and 2 independent 106.7mm heavy mortar battalions). Artillery battalions from the reserve of the high command, as is correct, were not attached to infantry divisions, but used instead to create field artillery groups that, composing corps and army artillery, provided support to infantry divisions operating on the main axis in the offense.

The American command had the ability to support the offensive of every infantry division simultaneously with 5-6 artillery battalions and 2 antiaircraft artillery battalions from the reserve of the high command, which were significantly more than normal reinforcing artillery assets as recommended in American regulations.

Ignoring the great significance that the Americans attached to the combat use of heavy mortars as an effective means of immediate support to the infantry, only two such independent heavy mortar battalions from the reserve of the high command were operational in Korea.

Artillery in the American forces used a number of well-known models of armaments, of which the best used in Korea were considered to be the 105mm and 155mm howitzers using mechanical drayage.

Even at the beginning of the war the 60mm bazooka was considered to be relatively ineffective against the tanks of the KPA and CPV, and that called for its replacement by the 88.9mm bazooka and the 105mm recoilless rifle.

During combat operations in Korea antiaircraft artillery in the American forces was primarily used to fire against ground targets. The Americans felt that automatic antiaircraft guns were not used with sufficient effect due to the poor knowledge of their combat capabilities by American infantry unit and formation commanders; antiaircraft gun crews also had insufficient skills in engaging ground targets.

Losses among American artillery in Korea for the period from 26 June 1950 to 10 May 1953 were more than 2,000 guns of all calibers and around 1,000 mortars. In view of these losses, the majority of the material component of the artillery knocked out of service was due to the premature replacement of components (barrels and mechanisms) as a result of the low technical quality of the material component, poor maintenance and conduct of fire without adhering to the firing regime.

It serves to pay attention to the good support provided to American artillery by aerial reconnaissance assets (2 observer aircraft per battalion). This in many cases simplified reconnaissance of the target, registration and firing for destruction under conditions of limited visibility from ground observation posts.

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