37 mm Gun M3

The 37 mm Gun M3 was the first dedicated anti-tank gun fielded by United States forces in numbers. Introduced in 1940, it became the standard anti-tank gun of the U.S. infantry with its size enabling it to be pulled by a jeep. However, the continuing improvement of German tanks quickly rendered the 37 mm ineffective, and by 1943 it was being gradually replaced in the European and Mediterranean theaters by the more powerful British-developed 57 mm Gun M1. In the Pacific, where the Japanese tank threat was less significant, the M3 remained in service until the end of the war.

Like many other light anti-tank guns, the M3 was widely used in the infantry support role and as an anti-personnel weapon, firing high-explosive and canister rounds.

The M5 and M6 tank mounted variants were used in several models of armored vehicles most notably in the Stuart Light Tank M3/M5, the Lee Medium Tank M3, and Greyhound Light Armored Car M8. In addition, the M3 in its original version was mated to a number of other self-propelled carriages.

37 mm Gun M3
Class Vehicle
Type Towed Artillery
Manufacturer Rock Island Arsenal
Production Period 1940 - 1943
Origin United States of America
Country Name Origin Year
United States of America 1940
Country Name Operational Year Retirement Year
Brazil View
China View
United States of America View
ManufacturerName Production From Production To Quantity
Watervliet Arsenal 1940 1943 View
Rock Island Arsenal 1940 1943 18702 View

In the mid-1930s, the United States Army had yet to field a dedicated anti-tank artillery piece; anti-tank companies of infantry regiments were armed with .50 in (12.7 mm) machine guns. Although there was some consideration had been given to replacing the machine guns with more a powerful anti-tank gun, the situation only began to change after the outbreak of the Spanish Civil War. Combat experience from Spain suggested that a light anti-tank gun, such as the German 37 mm PaK 35/36, was capable of neutralizing the growing threat posed by tanks.

In January 1937, the Ordnance Committee recommended development of a such a weapon; two PaK 36 guns were acquired for study. As the projected main user of the weapon, the Infantry branch was chosen to oversee the work. They wanted a lightweight gun which could be moved around by the crew, so any ideas of using a larger caliber than that of the German gun were discarded. The 37 mm was a popular caliber of anti-tank guns in the 1930s; other anti-tank guns of the same caliber included Swedish Bofors gun, Czechoslovakian vz. 34 and vz. 37, Japanese Type 94 and Type 1.

Development and testing continued until late 1938. Several variants of gun and carriage were proposed until on 15 December a combination of the T10 gun and T5 carriage was officially adopted as the 37 mm Gun M3 and Carriage M4. Although the weapon followed the concept of the PaK 36 and often referred to as a copy of it, the M3 differed significantly from the German design and used different ammunition.

The gun was manufactured by Watervliet Arsenal and the carriage by Rock Island Arsenal. The first pieces were delivered early in 1940, the production continued until 1943.

The M3 saw action for the first time during the defense of the Philippines in December 1941. It went on to become a factor in the Guadalcanal Campaign, where it was successfully employed against both Japanese armor and infantry. Throughout the war it remained effective against Japanese vehicles, which were thinly armored and were rarely committed in large groups. The light weight of the gun made it easy to move through difficult terrain; for example, when attacked by Japanese tanks on Betio during the Battle of Tarawa, Marines were able to heave the M3 over the 5 ft (1.5 m)-high seawall. While high explosive and canister ammunition proved useful in stopping Japanese infantry attacks, against enemy fortifications the M3 was only somewhat effective because of its small high-explosive projectile. Its overall effectiveness and ease of use meant the gun remained in service with the Marine Corps and with some Army units in the Pacific until the end of the war. Unhappy with the unusually low shield of the M3, some Marine Corps units extended it to provide better protection. These extensions sometimes had a scalloped top edge, intended to improve camouflage. A standard kit was tested in 1945, but was never issued.

The experience of the M3 in the North African Campaign was completely different. The gun was not powerful enough to deal with late production German Panzer III and IV tanks. After the nearly disastrous Battle of Kasserine Pass in February 1943, reports from some of the involved units mentioned 37 mm projectiles "bouncing off like marbles" from the turret and front armor of German medium tanks and proclaimed the gun "useless unless you have gun crews with the guts to stand and shoot from 100 yards". The Army was initially uncertain if these reports reflected the obsolescence of the weapon, or whether unrefined tactics and lack of experience were to blame. Yet on 26 May 1943 a new organization had the M3 replaced by the 57 mm Gun M1 (the U.S.-produced version of the British 6 pdr gun), with Dodge 1½ ton trucks as prime movers. Only by spring 1944 did the 57 mm gun reach the battlefield in large numbers.

Meanwhile, the Italian campaign was launched, and M3 guns saw action from the day of the Sicily landing on 10 July 1943. That day the 37 mm guns demonstrated once again both their effectiveness against pre-war tanks—when they helped to repel an attack by Italian Renault R 35s—and inability to cope with modern threats in a subsequent encounter with Tiger Is from the Hermann Göring division. The Italian theater had a lower priority for reequipment than Northwest Europe, and some M3s were still in use in Italy in late 1944.

By mid-1944, the M3 had fallen out of favor even with airborne troops, despite their strong preference for compact and lightweight weapon systems. The Airborne Command had rejected the 57 mm M1 in the summer of 1943 claiming its unfitness for airlifting and the Table of Organisation and Equipment (TO&E) of February 1944 still had airborne divisions keeping their 37 mm guns. Nevertheless, the 82nd and the 101st, were reequipped with British-manufactured 6-pounder gun (57 mm) on carriage Mk III (designed to fit into the British Horsa glider) for the Normandy airdrops. This change was officially introduced in the TO&E of December 1944.

The M3 was phased out of U.S. service soon after the end of the war.

Type Anti-tank gun
Place of origin United States
Service history
Used by United States
National Revolutionary Army
Wars World War II
Second Sino-Japanese War
Production history
Designed 1938
Manufacturer Gun: Watervliet Arsenal,
Carriage: Rock Island Arsenal
Produced 1940–1943
Number built 18702
Weight 413.68 kg (912.01 lb)
Length 3.92 m (12 ft 10.3 in)
Barrel length overall: 2.1 m (6 ft 11 in) L/56.6
bore: 1.98 m (6 ft 6 in) L/53.5
Width 1.61 m (5 ft 3.4 in)
Height 0.96 m (3 ft 1.8 in)
Crew 4–6
Shell 37×223 mm. R
Caliber 37 mm (1.45 inch)
Breech vertical block
Recoil hydrospring
Carriage split trail
Elevation -10° to +15°
Traverse 60°
Rate of fire up to 25 rpm
Muzzle velocity up to 884 m/s (2,900 ft/s)
Maximum firing range 6.9 km (4.29 mi)
Sights telescopic, M6

End notes