The M3 Gun Motor Carriage (GMC) was a

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

tank destroyer A tank destroyer, tank hunter, tank killer, or self-propelled anti-tank gun is a type of armoured fighting vehicle, armed with a direct fire artillery gun or missile launcher, designed specifically to engage and destroy enemy tanks, often wi ...

equipped with a 75 mm M1897A4 gun, which was built by the

Autocar Company The Autocar Company is an American specialist manufacturer of severe-duty, Class 7 and Class 8 vocational trucks, with its headquarters in Birmingham, Alabama. Started in 1897 in Pittsburgh, Pennsylvania, as a manufacturer of Brass Era automo ...

during World War II. After observing the new and often decisive, uses of armored vehicles on both sides during the French campaign of 1940, the US Army decided that it required a 75 mm

self-propelled gun Self-propelled artillery (also called locomotive artillery) is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled mo ...

, based on the chassis of the

M3 Half-track The M3 half-track was an American armored personnel carrier half-track widely used by the Allies during World War II and in the Cold War. Derived from the M2 half-track car, the M3 was extensively produced, with about 15,000 standard M3s and mor ...

. This was initially known as the T12. However, after the addition of features such as the

gun shield A U.S. Marine manning an M240 machine gun equipped with a gun shield A gun shield is a flat (or sometimes curved) piece of armor designed to be mounted on a crew-served weapon such as a machine gun, automatic grenade launcher, or artillery piece ...

from the M2A3 (a carriage for the M1897A4), the new vehicle entered production under the name M3 Gun Motor Carriage (or M3 GMC). Because the number of M2A3 gun shields available was insufficient for the M3 GMC order, a new gun shield was designed. Variants featuring the new shield were designated M3A1 GMC. The T12/M3 first served in the Philippines Campaign in 1942 with the Provisional Field Artillery Brigade in the anti-tank and the fire-support role. It then served in

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

in tank destroyer battalions. It was used ineffectively in the

Battle of Kasserine Pass The Battle of Kasserine Pass was a series of battles of the Tunisian campaign of World War II that took place in February 1943 at Kasserine Pass, a gap in the Grand Dorsal chain of the Atlas Mountains in west central Tunisia. The Axis forces, ...

and several other engagements, but was used with success in the

Battle of El Guettar The Battle of El Guettar was a battle that took place during the Tunisia Campaign of World War II, fought between elements of the Army Group Africa under General Hans-Jürgen von Arnim, along with Italian First Army under General Giovanni Messe ...

. It also served in the

Allied invasion of Sicily The Allied invasion of Sicily, also known as Operation Husky, was a major campaign of World War II in which the Allied forces invaded the island of Sicily in July 1943 and took it from the Axis powers ( Fascist Italy and Nazi Germany). It bega ...

, but was eventually superseded by the

M10 tank destroyer The M10 tank destroyer was an American tank destroyer of World War II. After US entry into World War II and the formation of the Tank Destroyer Force, a suitable vehicle was needed to equip the new battalions. By November 1941, the Army requeste ...

. A total of 2,203 were produced, of which 1,361 were converted back into M3A1 half-tracks. The M3 GMC also served in the

Pacific theater The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, starting with the

Battle of Saipan The Battle of Saipan was a battle of the Pacific campaign of World War II, fought on the island of Saipan in the Mariana Islands from 15 June to 9 July 1944 as part of Operation Forager. It has been referred to as the "Pacific D-Day" with th ...

. It proved effective against the Japanese

Type 95 Ha-Go The was a light tank used by the Empire of Japan during the Second Sino-Japanese War, at Battles of Khalkhin Gol, Nomonhan against the Soviet Union, and in the Second World War. It proved sufficient against infantry but, like the American M3 Stu ...

and

Type 97 Chi-Ha The was a medium tank used by the Imperial Japanese Army during the Second Sino-Japanese War, the Battles of Khalkhin Gol against the Soviet Union, and the Second World War. It was the most widely produced Japanese medium tank of World War II. T ...

tanks. It later served in the

Battle of Okinawa The , codenamed Operation Iceberg, was a major battle of the Pacific War fought on the island of Okinawa by United States Army (USA) and United States Marine Corps (USMC) forces against the Imperial Japanese Army (IJA). The initial invasion of ...

, the

Battle of Peleliu The Battle of Peleliu, codenamed Operation Stalemate II by the US military, was fought between the United States and Japan during the Mariana and Palau Islands campaign of World War II, from September 15 to November 27, 1944, on the island of ...

and many other island battles.

Specifications

The M3 GMC was 20.46 feet (6.24 m) long, 7.29 feet (2.22 m) wide, 8.17 feet (2.49 m) high (including the

), and weighed 20,000 pounds (9.1 t). Its suspension consisted of semi-elliptical longitudal

leaf spring A leaf spring is a simple form of spring commonly used for the suspension in wheeled vehicles. Originally called a ''laminated'' or ''carriage spring'', and sometimes referred to as a semi-elliptical spring, elliptical spring, or cart spring, it ...

s for the wheels and vertical volute springs for the tracks, while its transmission consisted of constant mesh. Its ground clearance was 11.2 inches (280 mm).Hunnicutt, p. 218.Ness, p. 207. It had a

White White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...

160AX 147 horsepower (110 kW), 386 cubic inch (6,330 cc), 6-cylinder engine with a compression ratio of 6.44:1. It had a 150-mile (240 km) range, 60 US gal (230 L) fuel tank, a speed of 47 mph (75 km/h), and a power to weight ratio of 14.7 hp per ton. It was armed with one 75 mm M1897A5 with 59 rounds, had 0.25–0.625 in (6.4–15.9 mm) of armor, and a crew of five consisting of a commander, gunner, two loaders, and a driver. The M3 (with the M2A3 mount) could traverse 19° left and 21° right, elevate 29° and depress −10°. The M3A1 (using the M5 mount) could traverse 21° in both directions, but could only depress −6.5°. Firing the M61 armor piercing round, the gun could penetrate up to of armor at .

Development

After the

fall of France The Battle of France (french: bataille de France) (10 May – 25 June 1940), also known as the Western Campaign ('), the French Campaign (german: Frankreichfeldzug, ) and the Fall of France, was the German invasion of France during the Second World ...

, the U.S. Army studied the reasons behind the effectiveness of the German campaign against the French and British forces. One aspect that was highlighted by this study was the use of

self propelled artillery Self-propelled artillery (also called locomotive artillery) is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled ...

, however by 1941 there was little available in the U.S. Army's arsenal that could be used in such a role. The Army had a number of M1897A5 guns, sufficient for the mass-production for such a weapon, and the M3 half-track was coming into production. After some debate, the Army decided to place M1897A5 guns on the M3 half-track chassis, which was designated the T12 GMC. The M1897A5 gun was originally adapted for the M3 chassis by placing it in a welded box riveted to the chassis behind the driver's compartment. It was accepted by the Army on 31 October 1941. A batch of 36 T12s was used for testing, while another 50 were built and transported to

the Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

.Zaloga, p. 33. The 36 T12s were improved in multiple ways. The improvements included the inclusion of a mount that raised the gun shield, the replacement of the original gun shield with the M2A3 gun shield, and the addition of a M2 Browning machine gun, which was later removed. After the final improvements were finished, the prototype vehicles were sent to the

for production.Zaloga, p. 22

M3A1

As the existing supply of M2A3 gun shields was insufficient to meet requirements for the production of the M3, the

Ordnance Department The United States Army Ordnance Corps, formerly the United States Army Ordnance Department, is a sustainment branch of the United States Army, headquartered at Fort Lee, Virginia. The broad mission of the Ordnance Corps is to supply Army comb ...

developed the M5 gun shield, which replaced the M2A3. The new design was designated as the M3A1 Gun Motor Carriage.

Service history

American use

The T12/M3 GMC first saw action with the U.S. Army in the Philippines in 1941–42, six months after it was designed. Fifty were shipped on convoys to the Philippines in the late summer and fall of 1941. Three battalions of the Provisional Field Artillery Brigade operated T12s against the Japanese when they invaded the Philippines. During the early part of the campaign, the vehicle was used to provide direct covering fire and anti-tank support. The Japanese captured a few vehicles in 1942 and used them in the defense of the Philippines. By 1942, M3 GMCs were being used by tank destroyer battalions in the North African Campaign, each of which consisted of 36 M3s and four 37 mm M6 GMCs. The M3 GMCs, which were designed for ambushing tanks, proved to be inadequate for this task in the battles of Sidi Bou Zid and Kasserine Pass, mainly due to poor tactics. Nevertheless, the M3 was later used in the

with success, claiming 30 German tanks, including possibly two

Tiger The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...

tanks, at the cost of 21 M3s. Some M3s also saw service in

(Operation Husky), but by that time, the

had replaced it in the U.S. Army. A total of 1,360 M3 GMCs were also converted back into M3A1 half-tracks. The M3 also served with the

U.S. Marines The United States Marine Corps (USMC), also referred to as the United States Marines, is the Marines, maritime land force military branch, service branch of the United States Armed Forces responsible for conducting expeditionary warfare, exped ...

in the Pacific Theater of Operations and was first used in the

invasion of Saipan The Battle of Saipan was a battle of the Pacific campaign of World War II, fought on the island of Saipan in the Mariana Islands from 15 June to 9 July 1944 as part of Operation Forager. It has been referred to as the "Pacific D-Day" with the ...

. It proved highly effective against the

and the

, in the fight against the Japanese 9th Tank Regiment on Saipan. It also served in the

and the

, and many other conflicts in the Pacific.Zaloga, p. 35.

Allied use

The M3 GMC saw limited service with other countries as it was not widely supplied through the

Lend-Lease program Lend-Lease, formally the Lend-Lease Act and introduced as An Act to Promote the Defense of the United States (), was a policy under which the United States supplied the United Kingdom, the Soviet Union and other Allied nations with food, oil, ...

. A small batch of 170 vehicles was supplied to Britain, which used them in their Armoured Car Regiments which were the reconnaissance units of the armored formations. They were first used in the

Tunisian Campaign The Tunisian campaign (also known as the Battle of Tunisia) was a series of battles that took place in Tunisia during the North African campaign of the Second World War, between Axis and Allied forces from 17 November 1942 to 13 May 1943. The ...

with the

Royal Dragoons The Royal Dragoons (1st Dragoons) was a heavy cavalry regiment of the British Army. The regiment was formed in 1661 as the Tangier Horse. It served for three centuries and was in action during the First and the Second World Wars. It was amalgam ...

. They were also used in Sicily,

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, and later in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

, but were gradually retired. The

Free French Army Free France (french: France Libre) was a political entity that claimed to be the legitimate government of France following the dissolution of the Third Republic. Led by French general , Free France was established as a government-in-exile ...

also used M3s for training before receiving M10 tank destroyers. With two issued per squadron in practice they were used as an eight gun regimental artillery battery.Crow, Duncan, AFV Weapons Profile Book No.2 ''British and Commonwealth Armoured Formations (1919-1946)'', Profile Publishing p.102-104

Production

A total of 2,202 M3 GMCs were produced from 1941 to 1943. Only 86 vehicles were produced in 1941, but production increased to 1,350 in 1942, with the remaining 766 completed in 1943. Production was stopped due to the introduction of turreted, purpose-built, tank destroyers, such as the M10 GMC.Ness, p. 196.

References

Citations

Bibliography

* Berndt, Thomas (1993). ''Standard Catalog of U.S. Military Vehicles''. Iola, WI: Krause Publications. * Berndt, Thomas (1994). ''American Tanks of World War II''. Minnesota, MN: MBI Publishing Company. * Hogg, Ian V.; Weeks, John S. (1980). ''The Illustrated Encyclopedia of Military Vehicles''. Englewood Cliffs, NJ: Prentice-Hall. * Hunnicutt, R. P. (2001) ''Half-Track: A History of American Semi-Tracked Vehicles''. Navato, CA: Presidio Press. * Mesko, Jim (1996). ''M3 Half-tracks in Action''. Carrollton, TX: Squadron/Signal Publications. * Ness, Leland S. (2002). ''Jane's World War II Tanks and Fighting Vehicles''. New York, NY: HarperCollins. * Zaloga, Steven J. (1994). ''M3 Infantry Half-track 1940–1973'', Oxford: Osprey Publications. {{DEFAULTSORT:M3 GMC World War II tank destroyers of the United States World War II self-propelled artillery Self-propelled artillery of the United States World War II half-tracks Half-tracks of the United States Military vehicles introduced from 1940 to 1944