Operation Overlord
Special Study: The US Army Field Artillery
Note: At the beginning of World War Two, the artillery of the US Army was divided into two branches: the Field Artillery (FA), nicknamed the Redlegs (after the red trouser stripes worn by Civil War-era artillerymen of the Union armies), and the Coast Artillery Corps (CA), nicknamed the Cosmoliners (after the preservative grease used to protect coast artillery guns from salt water corrosion). This article covers the FA only.
World War II FA weapons were of two types: guns and howitzers. The former were medium- to long-range, flat-trajectory weapons; the latter were medium-range weapons capable of high-trajectory fire.
When it was all over, General George S. Patton said, “I do not have to tell you who won the war. You know. The artillery did.”
There was some hyperbole in this, but Patton had a point. Without doubt, the Field Artillery was the most impressive branch of the wartime US Army’s combat arms. Its weapons and equipment were of the highest quality; its technical and tactical competence was second to none. The Army had closely studied the lessons of the Great War, particularly as related to the role of artillery. When the time came to prepare for a new war, the organization of the FA was carried out systematically. Rather than thinking simply in terms of guns, men and units, the Army created an integrated artillery weapons system.
But still, without guns there is no artillery. In the Great War, the FA had been reliant on French equipment: the M1897 75mm field gun, the M1917 155mm gun and the M1917 155mm howitzer. These weapons soldiered on in the postwar army and saw service in the early days of World War II, but by then a new range of weapons had been designed to replace them. The artillery of the infantry division came to be based on two models: the M2A1 105mm light field howitzer and the M1 155mm medium field howitzer. Both were excellent weapons, destined to serve for many years. Modernized versions of both equipped National Guard artillery units as late as the 1980s.
By 1942 these weapons were well integrated into the Army’s combat divisions. In 1940-41 the infantry divisions of the Regular Army had been reorganized from the World War I-era square configuration (two infantry brigades, each with two regiments) to a triangular configuration (three infantry regiments, each with three battalions). The triangular division’s artillery component consisted of four separate FA battalions, three with 12 x M2A1 105mm howitzers each, and one with 12 x M1 155mm howitzers. These four battalions were controlled by the Division Artillery (DIVARTY), essentially a brigade-echelon tactical headquarters. (The infantry divisions of the National Guard remained in the square configuration until they were inducted into federal service in 1940-41, at which time they were triangularized.)
In 1941, armored divisions were organized under what later was termed the heavy configuration. Their artillery component consisted of seven batteries, each with 4 x 105mm howitzers, halftrack towed. Four of these batteries were under a regimental headquarters in the division’s armored brigade; the other three were in a separate battalion. There was no DIVARTY HQ. In 1942, armor division artillery was reorganized into three battalions, each with 18 x self-propelled (SP) 105mm howitzers and the regimental HQ was reorganized as a DIVARTY HQ. When most armored divisions were converted to the 1943 light configuration, their artillery component remained the same: three Armored FA Battalions, as by then they were designated, under a DIVARTY HQ.
The DIVARTY of airborne divisions had three battalions, each with 12 x M1 75mm pack howitzers: one designated Parachute FA Battalion, the other two designated Glider FA Battalion. in 1943-44 a fourth Glider FA Battalion equipped with the M3 105mm light howitzer was attached to some airborne divisions, and by early 1945 this battalion was present in all airborne divisions. The two cavalry divisions in existence in 1941 had three FA battalions: two with 12 x 75mm howitzers each, horse drawn, and one with 12 x 105mm howitzers, truck towed. Neither division, however, saw action as horse cavalry during the war.
The Army's nondivisional artillery consisted mostly of howitzers and guns with a caliber of 4.5in (115mm) or greater, though there were some 105mm SP howitzer battalions. Such units were intended to serve as corps and field army assets, and at the beginning of the war they were organized as regiments and brigades.
In late 1942, however, the Army decided to abolish the regimental structure in all branches but infantry, replacing it with a flexible group organization. Nondivisional FA regiments were reorganized as follows (using the 333rd FA Regiment as an example). The regimental headquarters became Headquarters and Headquarters Battery (HHB) 333rd FA Group, the 1st Battalion became the 333rd FA Battalion, and the 2nd Battalion became the 969th FA Battalion. All three were then separate, self-contained units, though usually the battalions were attached back to the group. An FA group could control up to four battalions, as did the 333rd FA Group during the Battle of Normandy. Most FA brigades were inactivated, though some, already overseas, remained in being.
Nondivisional FA battalions were equipped with the following weapons: M7 105mm (SP), M1 155mm, M1 8in and M1 240mm howitzers; M1 4.5in, M1 and M40 (SP) 155mm and M1 8in guns. The 105mm SP, 4.5in and 155mm battalions had twelve guns or howitzers; the 8in and 240mm battalions had six. A typical allotment of nondivisional artillery to a corps or field army was XV Corps Artillery on 6 June 1944.
Unlike the artillery of the German Army, which remained partly reliant on horses for mobility, the US Army’s FA battalions were completely motorized or mechanized. The Armored FA Battalion’s M7 SP 105mm howitzer (based on a modified M3 or M4 tank chassis) greatly enhanced the weapon’s mobility and provided its crew with a measure of armor protection. The infantry division’s 105mm howitzers were towed by the ubiquitous 2.5-ton cargo truck; heavier guns by various models of tractor. A towed 105mm howitzer battery in an infantry division had 7 x 2.5-ton trucks, 5 x 0.75-ton trucks (known as the weapons carrier) and 3 x 0.25-ton trucks (the famous Jeep). There were also five trailers of various cargo capacities.
The Army’s FA weapons system integrated the core tasks relating to artillery: observation, target acquisition, communications, and fire direction. It was this system that made the US Army artillery so effective in action.
Observation was just that: observing and correcting the fall of shot to adjust fire onto the target. This was the job of the FA forward observer (FO) teams. These teams were attached to infantry and armor units and were linked by radio to the fire direction center (FDC) of their parent FA battalion. Their presence on the front line enabled targets of opportunity to be quickly identified and accurately engaged: the FA direct support mission.
It was found, however, that insufficient FO teams could be provided to guarantee timely artillery support for dispersed infantry and armor units in action. This gap was filled by air observation. In infantry and armored divisions the DIVARTY headquarters and each FA battalion had an air observation section with two light liaison aircraft for a total of ten in the infantry division or eight in the armored division. The aircraft was either the L-4 Grasshopper, a militarized variant of the popular Piper J-3 Cub, or the Stinson L-5 Sentinel, purpose built for the military. Though the Air Corps provided ground crews and technical support, the air observation sections were part of the FA, the pilots and observers being FA officers. The ability to spot targets and call for fire from the air greatly enhanced the FA’s flexibility.
Despite its designation, the Field Artillery Observation Battalion was primarily concerned with target acquisition on behalf of nondivisional corps artillery. These battalions were organized with a headquarters battery and two observation batteries, each of which had a sound ranging platoon and a flash ranging platoon. The battalion’s missions were location of hostile artillery, registration and adjustment of artillery fire, coordination of survey, artillery calibration, and providing the meteorological message to supported units.
Secure, rapid communication was facilitated by the signal units attached at each echelon of command, providing FA units with their own radio and field telephone nets. The FM radio had been adopted before the war and it proved very satisfactory in service. Higher headquarters (corps artillery, DIVARTY and FA group) maintained a command net linking to their subordinate battalions, and battalion headquarters did likewise, linking to their subordinate batteries. This enabled calls for fire from observers and fire orders from higher headquarters to be passed quickly along the chain of command.
FA fire direction had two facets: tactical and technical. Tactical fire direction dealt with the coordination of FA fires with overall tactical planning: identification and prioritization of targets, preparation of fire plans, standardization of fire commands, employment of smoke, and integration of other assets, such as infantry regiment cannon companies and 4.2in mortar units, into fire planning. In divisions, tactical fire direction was the responsibility of the operations section of the DIVARTY HQ, though some tasks could devolve on the battalion fire direction centers (FDC). Tactical fire direction of nondivisional FA units was provided by the corps artillery or FA group headquarters.
Since all echelons of command were linked by field telephone and radio nets, FA fires could be divided or massed as required. The most fearsome massing of fires was the time-on-target (TOT) mission, by which the fires of multiple FA batteries or battalions were timed to strike a target simultaneously—with devastating effect.
Technical fire direction—the actual computation of firing data for howitzers and guns—was done at the battalion and firing battery levels. The technical fire direction process converted range and direction to the target from each battery position into elevation, deflection and fuse settings on the gun line, with such variables as propellant temperature, meteorological conditions, and differences in altitude between the guns and the target incorporated into the solution. Standardized procedures enabled this task to be completed rapidly by well-trained FDC personnel.
Depending on the type of weapon, FA howitzers and guns could fire several types of ammunition. The most common by far was shell HE (high explosive) with fuse quick (point detonating) or fuse time. Late in the war, the FA began to receive fuse variable time (proximity detonating). Other shell types were illumination, chemical smoke, and white phosphorus, all with fuse time. Ammunition was either fixed (shell, fuse, and propelling charge as a single unit), semi-fixed (shell/fuse and propelling charge in separate units), or separate loading (shell/fuse and bagged propelling charge.) The size of gun crews varied according to the weapon. An eight-man crew was specified for the M2A1 105mm howitzer.
During the Battle of Normandy, the Redlegs performed splendidly. Though they had no very high opinion of the American infantry, numerous German soldiers, from enlisted men to senior officers, testified that the FA was the most respected and feared branch of the US Army. The statistics reveal why. Postwar analysis disclosed that in Tunisia, Sicily, Italy, and northwest Europe, some 85-90% of total casualties inflicted by US forces on the German enemy were due to artillery fire. In World War II, the Field Artillery well earned its title: “King of Battle.”
My German grandfather served in Russia until 1943 and then in Italy to meet the Allied invasion.
He thought that American artillery was the most dangerous he ever saw.
Paraphrase.
"Russian artillery destroyed everything, but American artillery found you. "
According to VDH, this is how the Americans won the European theatre.