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Rich Anderson Articles
US Army in WWII
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US Army in World War II
US Army in World War II
Artillery and AA Artillery

by Rich Anderson

Chemical Weapons

The 4.2" mortar battalions provided chemical warfare (WP, smoke, and gas) support to Army divisions. Originally without an HE capability, inasmuch as there were no HE rounds for the 4.2" mortar, in late 1942 a bright CW officer thought that it would be a good idea to provide an HE round for the piece. As a result the chemical mortars were available to provide welcome heavy mortar support for the infantry by 1943. By the fall of 1944 there were sufficient battalions in the ETO to allow for a normal assignment of one company per infantry division. In some circumstances this would be augmented to a full battalion.

The 2nd, 3rd, 81st, 83rd, 86th, 87th, 89th, 90th, 91st, 92nd, 93rd, 94th, 95th, 96th, 97th, and 99th Battalions served in the ETO. The 84th and 100th Battalions served in Italy. The 71st, 80th, 82nd, 85th, 88th, and 98th Battalions served in the PTO.


In World War I the artillery arm of the U.S. Army had fought in Europe equipped entirely with French or British weapons. There were many reasons for this: the need to standardize Allied arms, lack of shipping space, and lack of industrial capacity. However, another factor was that many ordnance specialists in Britain and France felt that the indigenous American gun designs were not up to European standards. As a result, in 1921 the U.S. Army Chief of Staff, General Charles P. Sommerall (one of the most brilliant artillerymen in U.S. Army history) established the Westervelt Board to examine the army's ordnance requirements for the future. The board's report was impartial and farsighted, and it had dramatic consequences for the U.S. Army artillery in World War II. The board recommended that the standard divisional artillery piece be increased in caliber from 75mm to 105mm, while the general support weapon for the division was to be standardized as the 155mm howitzer. The 4.7" corps general support gun (a British design) was to be discarded in favor of the 155mm gun (a French design). In addition, the board recommended that heavier pieces of the most modern type be designed, and that all artillery pieces be suitable for rapid motorized road movement. Finally, improvements in fire control methodology and communications were recommended, based upon concepts that had been pioneered by Summerall as an artillery brigade commander in France.

The financial climate of the 1920s and 1930s delayed the deployment of such an improved artillery system. However, sufficient funding was available to allow innovative Artillery and Ordnance officers to continue experimenting with new gun designs and doctrine. As a result, when the Army began to expand, much of the background work to modernize the artillery was already complete. Designs had been completed and prototypes developed and tested for most of the guns and howitzers that were to see service during the war (the opposite of the situation in the new Armor Branch, where prohibitive cost had stymied design work on armored vehicle prototypes and doctrinal experimentation during the 1920s and 1930s).

Divisional pieces included the M1 105mm howitzer and the M1 155mm howitzer. Both were excellent weapons, with good range and, particularly in the case of the 155mm, excellent accuracy. Other new weapons were the M1 75mm pack howitzer and the M3 105mm howitzer. Both were lightweight and could be easily broken down into manageable loads suitable for transportation by pack animal (horse, mule, or man as available) or by air, and if relatively short-ranged, were ideal for airborne forces. The M3 also saw service after 1943 in the Cannon Company of the infantry regiment. A SP version of the M1 105mm, the M7 Priest, also equipped the field artillery battalions of the armor division.

Non-divisional artillery pieces included battalions equipped with these same weapons, as well as other, heavier pieces. A companion of the 155mm howitzer was the 4.5" gun (an indigenous 120mm gun was one of the few failures of the inter-war design projects). The tube of this gun was of British design, while the carriage was that of the 155mm howitzer (carriage commonality between companion guns and howitzers was one of the hallmarks of U.S. artillery designs). Unfortunately, the 4.5" -- although well liked by American artillerymen - was not a very efficient weapon for its size. The shell (also of British design) was of low-grade steel, thick-walled and with a small bursting charge compared to the shell weight. The 4.5" projectile weighed 54.90 pounds, but had only a 4.49 pound bursting charge, while the 105mm howitzer projectile weighed 33 pounds, but had a 4.8 pound bursting charge. Its range was insufficient to compensate for the relative ineffectiveness of this round and as a result it was withdrawn from service soon after the end of the war.

A much more effective weapon was the M1 155mm gun, known as a "Long Tom" (an appellation with a long and glorious tradition in the U.S. artillery.) It combined long range, accuracy, and hitting power with a well designed, mobile carriage.

A different 155mm gun was the M12 SP. Developed in 1942, it was an interesting amalgam of the old and the new, utilizing the tube of the pre-war French designed GPF (Grand Puissance, Failloux), itself developed in World War II, and the chassis of the obsolescent M3 Grant tank. It was an experiment by the Ordnance Department that had been turned down by the AGF in October 1943 on the grounds that there was no requirement for it. However, in early 1944 urgent requests from U.S. Army forces in England for a heavy SP gun resulted in 74 being rebuilt. They eventually equipped seven field artillery battalions in the ETO and proved invaluable. An improved model, the M40, based upon the M1 gun and M4 tank, was produced in 1944 and deployed in limited numbers to the ETO in March 1945.
Heavier supporting artillery pieces were the M1 8" howitzer, an excellent and accurate weapon; the M1 8" gun, which was developed as an answer to the superb German 17cm gun, had greater range and a more lethal shell than the German weapon, but suffered from poor accuracy and excessive barrel wear; and the 240mm howitzer, a good, if very heavy, weapon.

Nearly all US artillery battalions were organized with three firing batteries and a total of twelve tubes. The exception was the eighteen-tube armored field artillery battalion and the six-tube 8" gun and 240mm howitzer battalions. A major advantage for the American artillery was that it was fully motorized and highly mobile. All 105mm and 155mm howitzer battalions in the ETO were truck-drawn, although a Table of Equipment (TE) for a tractor-drawn 155mm battalion existed. The 155mm gun battalions were almost all tractor-drawn, although a few evidently were also truck-drawn. The 4.5" gun, 8" gun, 8" howitzer, and 240mm howitzer battalions were all tractor-drawn, although, again, a TE for truck drawn battalions existed. The standard prime mover was a two-and-one-half ton truck for the 105mm and a 4-ton Diamond T truck for the 155mm howitzers. Tractors included the M5 thirteen-ton prime movers, which were utilized for the 105mm M2 howitzer, the 4.5" gun, and 155mm M1 howitzer, and the M4 eighteen-ton hi-speed, full-track, heavy prime mover, which was utilized for the 3" AA gun, the 90mm AA gun, the 155mm Long Tom gun, 8" howitzer, 8" gun, and 240mm howitzer. Redundant M3 medium tank chassis, without armament, and M31 and M32 armored recovery vehicles were also utilized as prime movers for the heavier artillery pieces.
Non-divisional artillery battalions were normally subordinated to field artillery groups. The groups were formed in 1943 from the headquarters battery of the broken up field artillery regiments. The field artillery group consisted of an H&H Battery, with a command element and a fire-direction center element, and a Service Battery. A group was usually assigned from two to six battalions, although one or more of the battalions might be attached for direct support of an individual division. Usually, the groups were assigned howitzer and gun battalions of companion caliber, that is, 155mm howitzers were grouped with 4.5" guns, 8" howitzers with 155mm guns, and 8" guns with 240mm howitzers. The normal ratio was one gun battalion for every two howitzer battalions, although this was not always firmly adhered to. Separate 105mm howitzer battalions were normally grouped together, but were almost always assigned to direct support of divisions. The 155mm SP gun battalions were assigned to groups as the tactical situation warranted, or were frequently attached, by battery or battalion, to armored or infantry divisions.

Field artillery brigades were also created, originally to command the separate field artillery regiments and later, to command the field artillery groups. However, the brigade eventually was seen as a redundant and unnecessary additional layer of command. Most of the brigades were inactivated or were redesignated as H&H batteries and assigned to different corps and divisions. A few artillery brigades were retained and served as such, the 13th in the MTO and the 32nd, 33rd, 34th, and 61st in the ETO. In the First Army in the ETO, two field artillery groups were attached to the 32nd Field Artillery Brigade. The brigade controlled all 8" gun and 240mm howitzer battalions of the army, making it, in effect, a heavy artillery brigade. A similar, but less centralized system was followed by Third, Seventh, and Ninth armies for control of their heavy battalions.

All in all, the U.S. artillery was equipped with armament that was at least as well designed as, if not better than, any other in the world. The U.S. artillery further benefited from communications equipment and a fire control system that was equaled only by that of the Royal Artillery. Individual forward observers operated close to the front lines and had access, via powerful radios and extensive telephone landlines, to a formidable array of weapons. The highly redundant signals system meant that, even when all other contact with front-line units and their headquarters was lost, the artillery communications net usually remained open.

Perhaps more important, and making the U.S. artillery the best in the world, was a fire-direction system that had been develop at the U.S. Field Artillery School at Fort Sill, Oklahoma, between the wars. This was a highly refined development of the crude system Summerall had pioneered in World War I. This system permitted rapid engagements of targets, and allowed the coordination of fires of many units from many widely separated firing positions. One of the most deadly tactics employed was the time-on-target (TOT) concentration. A TOT massed fires from several battalions onto a selected target and calculated the times of flight for the shells from each battery so that they all arrived on target at nearly the same instant (a similar tactic, called a "Stonk", had been developed independently by the Royal Artillery in North Africa).

Further enhancing the deadliness of the U.S. artillery was the development and deployment in the ETO in December 1944 of the new proximity fuse. Also known by its code designation of VT (for variable-time) or POZIT, the proximity fuse contained a tiny radar that triggered detonation at a preset distance from a solid object. The POZIT fuse had been intended for use against air targets (taking a heavy toll of German "Buzzbombs" in the fall of 1944). The fuse significantly simplified and enhanced the lethality of air bursts and eliminated the need for complicated and unreliable time fuses.

Although US artillery was second to none in the war, problems with ammunition supply did hamper efficiency at various periods. This problem reached its nadir during the fall of 1944, when the US artillery in Europe was reduced to strict rationing of ammunition. At one point, the artillery was limited to fewer than twenty 105mm rounds-per-day-per-gun. From 11 October to 7 November 1944, Third Army fired a total of 76,325 rounds of all types (an average of 2,726 per-day), which was less than the number fired on a single day during the Battle of the Bulge. Indeed, at the end of the Battle of the Bulge, ammunition reserves in the ETO were 31 percent of the War Department's planning levels (which were already conceded to be too low). Like the personnel replacement problem, the ammunition shortage was only truly solved by the ending of the war.

Initially, the troop basis allotted by the AGF for non-divisional artillery was somewhat low, and it emphasized lighter artillery over heavier. Only fifty-four heavy and eighty-one medium battalions, compared to 105 light battalions, were authorized on 24 November 1942. However, lobbying by Generals McNair and Sommervell in 1943 resulted in an increase. On 15 January 1944 the War Department authorization had expanded to include 111 heavy and 111 medium battalions, while the number of light battalions authorized had decreased to 95. In April 1944 a review of combat experience by the Lucas Board resulted in a further expansion, with 143 heavy and 114 medium battalions authorized on 1 July 1944. Converting light artillery battalions made up most of the increased numbers, by 1 July the authorized number of light battalions was down to eighty. On 31 December 1944 the artillery reached its maximum strength. On that date there were a total of 346 battalions active, 137 heavy, 116 medium, and 93 light. On 31 March 1945 there were 137 heavy, 113 medium and 76 light battalions active, of which 307 were deployed or were about to deploy to active theaters of war.

As of 8 May 1945 there were a total of 238 separate field artillery battalions in the ETO, including:

    Four 75mm howitzer battalions:

The 463rd Parachute, 464th Parachute, 601st Pack, and 602nd Pack;

    Thirty-six 105mm howitzer battalions:

The 18th, 25th, 70th, 74th, 76th, 115th, 130th, 162nd Puerto Rican, 170th, 193rd, 196th, 241st, 242nd, 250th, 252nd, 255th, 280th, 281st, 282nd, 283rd, 284th, 394th, 401st, 512th, 522nd Nisei, 569th, 580th, 583rd, 627th, 687th, 688th, 690th, 691st, 692nd, 693rd, and 802nd;

    Sixteen 105mm Armored Field Artillery Battalions (105mm SP):

The 58th, 59th, 62nd, 65th, 69th, 83rd, 87th, 93rd, 253rd, 274th, 275th, 276th, 400th, 440th, 695th, and 696th; 

    Seventeen 4.5" gun battalions:

The 172nd, 176th, 198th, 211th, 215th, 259th, 770th, 771st, 772nd, 773rd, 774th, 775th, 777th Colored, 935th, 939th, 941st, and 959th;

    Seventy-one 155mm howitzer battalions:

The 2nd, 17th, 36th, 81st, 141st, 177th, 179th, 182nd, 183rd, 186th, 187th, 188th, 191st, 202nd, 203rd, 204th, 208th, 209th, 228th, 254th, 257th, 333rd Colored, 349th Colored, 350th Colored, 351st Colored, 521st, 550th, 665th, 666th, 667th, 670th, 671st, 672nd, 673rd, 686th Colored, 689th, 751st, 752nd, 753rd, 754th, 755th, 758th, 759th, 761st, 762nd, 763rd, 764th, 767th, 768th, 776th, 805th, 808th, 809th, 937th, 938th, 940th, 942nd, 943rd, 945th, 949th, 951st, 953rd, 955th, 957th, 961st, 963rd, 965th, 967th, 969th Colored, 974th, and 975th;

    Thirty 155mm gun battalions:

The 190th, 200th, 240th, 244th, 261st, 273rd, 514th, 515th, 516th, 528th, 540th, 541st, 546th, 547th, 548th, 549th, 559th, 561st, 634th, 635th, 731st, 733rd, 734th, 976th, 977th, 978th, 979th, 980th, 981st, and 989th;

    Six 155mm SP gun battalions:

The 174th, 258th, 557th, 558th, 987th, and 991st;

    Thirty-eight 8" howitzer battalions:

The 194th, 195th, 207th, 264th, 529th, 535th, 578th Colored, 630th, 656th, 657th, 658th, 659th, 660th, 661st, 662nd, 663rd, 736th, 738th, 739th, 740th, 741st, 742nd, 743rd, 744th, 745th, 746th, 747th, 748th, 787th, 788th, 790th, 791st, 793rd, 932nd, 933rd, 995th, 997th, and 999th Colored; 

    Five 8" gun battalions:

The 153rd, 243rd, 256th, 268th, and 575th;

    And fifteen 240mm howitzer battalions:

The 265th, 266th, 267th, 269th, 270th, 272nd, 277th, 278th, 538th, 539th, 551st, 552nd, 553rd, 697th, and 698th.

As of 8 May 1945 there were a total of sixteen separate field artillery battalions in the MTO, including:

    One 105mm howitzer battalion:

The 175th; 

    Two Armored Field Artillery Battalions (105mm SP):

The 432nd and 1125th;

    Seven 155mm howitzer battalions:

The 75th, 178th, 248th, 631st, 765th, 766th, and 936th;

    Four 155mm gun battalions:

The 173rd, 530th, 633rd, and 985th;

    Two 8" howitzer battalions:

The 527th and 536th.

As of 8 August 1945 there were a total of fifty-three separate field artillery battalions in the PTO, including:

    Three 75mm howitzer battalions:

The 462nd Parachute, 612th Pack, and 613th Pack; 

    Eight 105mm howitzer battalions:

The 97th, 134th, 147th, 148th, 249th, 251st, 260th, and 694th;

    Three Armored Field Artillery Battalions (105mm SP):

The 426th, 427th, and 428th; 

    Sixteen 155mm howitzer battalions:

The 4th, 55th, 145th, 154th, 165th, 181st, 198th, 225th, 429th, 756th, 757th, 760th, 769th, 803rd, 804th, and 947th;

    Eight 155mm gun battalions:

The 168th, 223rd, 226th, 433rd, 517th, 531st, 532nd, and 983rd; 

    Seven 8" howitzer battalions:

The 465th, 655th, 749th, 750th, 786th, 789th, and 797th;

    One 8" gun battalion:

The 780th; 

    Five 240mm howitzer battalions:

The 543rd, 544th, 545th, 778th, and 779th; 

    Two 4.5" rocket battalions:

The 421st and 422nd.

Antiaircraft Artillery

At the beginning of World War II the US antiaircraft artillery force was very much the poor stepchild of the Coast Artillery Corps. The units were mostly three battalion (a gun battalion, an automatic weapons battalion, and a searchlight battalion) regiments and separate battalions. They were equipped with a motley mix of obsolescent 3" guns and single barrel water-cooled .50 caliber machine guns. The German Blitzkrieg in Europe forced a widespread reevaluation of the Army's AAA capability and, beginning in 1940-1941 a vast expansion of the arm (it finally achieved an identity separate from the Coast Artillery in 1943). On 30 September 1942, it was proposed that 811 AAA battalions be organized (with a total strength of 619,000 men).
However, this massive buildup of AAA units became largely redundant when another formerly poor relation of the US Army, the Army Air Corps, wrested command of the air from the Luftwaffe in 1943 and 1944. Many AAA battalions were disbanded to provide replacements in 1944, some were converted to artillery. A total of 258 battalions were inactivated or disbanded between 1 January 1944 and 8 May 1945. Nevertheless, AAA remained a strong component of the army and achieved something of resurgence in late 1944 in Belgium, defending Antwerp from the threat of the V-1 "Buzzbomb." On 31 December 1944, there was still a total of 347 AAA battalions (with 257,000 men) active in the Army.

In 1943 the AAA regiments were broken up into separate battalions, with the regimental H&H companies becoming new AAA Group Headquarters. The AAA battalions were organized as either gun (equipped with the M1 90mm AA gun) or automatic weapons (equipped initially with a U.S.-designed M1 37mm gun, but later almost wholly re-equipped with the famous M1 40mm Bofors-designed gun, and with the M51 or M55 quad-mount .50 caliber machine gun). Battalions were further classified as mobile (that is towed), SP (utilizing halftrack-mounted guns, the M16, a quad .50 caliber mounting, and the M15, a combination mounting twin water-cooled .50 caliber and a single 37mm), or semi-mobile (with a reduced number of prime movers, designed for the defense of static installations).
The automatic weapons battalions of all types were organized with four firing batteries, lettered A to D, an H&H Battery, and a Service Battery. Each battery nominally contained eight towed 40mm or 37mm SP guns and eight quad .50 caliber towed or SP machine guns. However, many slight variations existed, some battalions had batteries composed of eight towed 40mm guns, four quad .50 caliber mounts, and eight single, water-cooled .50 caliber machine guns (there was a shortfall in production of the M51 and M55 mounts). Gun battalions were organized identically, except the batteries were equipped with four 90mm guns each and, usually, three water-cooled .50 caliber machine guns.
Normally, an AAA automatic weapons battalion was attached to each division, SP if attached to an armored division, and mobile if attached to an infantry division. A corps normally had one or more AAA groups attached. Each AAA group consisted of two or more automatic weapons battalions (usually mobile), although a gun battalion was occasionally attached. In the European Theater, gun battalions were more frequently found in AAA groups attached to the army or army group. Antiaircraft brigades were also formed and were normally attached to armies or to theater commands. In addition, the IX Air Defense Command (in effect an AAA division, originally organized as a part of the US Ninth Tactical Air Force), with an average of ten to fifteen gun and automatic weapons battalions, formed a powerful AAA reserve for the US 12th Army Group in Europe.
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Copyright © 2000 Rich Anderson.

Written by Rich Anderson. If you have questions or comments on this article, please contact Rich Anderson at:

About the author:
Richard C. Anderson, Jr. works as the Chief Historian at the The Dupuy Institute (a non-profit organization dedicated to scholarly research and objective analysis of historical data related to armed conflict and the resolution of armed conflict. The Dupuy Institute provides independent, historically-based analyses of lessons learned from modern military campaigns.

Published online: 2000.
Last Modified: 02/11/2007.

* Views expressed by contributors are their own and do not necessarily represent those of MHO.
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