The American half-track

The M3 half-track and its large family

Half-tracked vehicles are among World War II’s most evocative images. They were developed before the war and in anticipation of it, and while some of them persisted for decades afterward, they nevertheless largely faded out of use after the conflict where they made their debut. They were truly the vehicles of a specific era, and this article will introduce one of best-known examples: the American M3 half-track and its almost uncountable variations.

The half-track concept was born out the changes the tank brought to the battlefield late in World War I. Heavily armed and armored, decently fast and with good off-road ability (once their teething problems were worked out), tanks were ideal for breaking through enemy lines and attacking targets behind the front. They did, however, had a big weakness: they needed to be accompanied by infantry who could spot and eliminate enemy anti-tank weapons. Soldiers could not keep up with tanks on foot, though, so they needed their own vehicles to ride in.
 
The truck seemed like an obvious solution, but was a deeply flawed one: it offered practically no protection for the men inside, and also couldn’t keep up with tanks on rough terrain, or in deep mud where it would get bogged down. The infantry needed a special, purpose-built vehicle.

That vehicle was the half-track, which was designed to be a jack-of-all-trades: it was better off-road than wheeled vehicles, and better on-road than tracked ones. The tracks in the back greatly increased the surface area along which the vehicle pressed against the ground. This gave it better traction, and also lowered ground pressure, which made it less likely to sink into soft soil or mud. Another specific consideration in the U.S. was that civilian truck factories should be able to assemble the vehicle cheaply and in large numbers, using as many commercially available and proven components as possible.

The first iteration of America’s World War II half-tracks was the M2 half-track. Inspired by earlier French half-tracks, the M2 was originally designed as an artillery tractor that could pull an artillery piece while seven artillery crewmen and the ammunition rode in the back. It was closely based on the M3 Scout Car, with the relationship pretty obvious when you look at the two vehicles from the front. The M2 quickly found new niches in carrying machine gun squads and as a reconnaissance vehicle.

Being essentially a regular truck with the rear wheels replaced by a pair of short tracks made the M2 easy to manufacture and drive; the latter was a significant advantage, since driving licenses were much less common at the time, and a regular truck driver without any extra training for tracked vehicles was already considered a specialist job. This simplicity, however, also led to one of the M2’s (and later American half-tracks’) major flaws. The vehicle was a rear-track drive, but the steering was done entirely through the unpowered front wheels, and those two wheels just weren’t heavy enough to properly steer the vehicle while it was being propelled forward by a pair of powerful and heavy rear tracks. As a result, American half-tracks had a very large turning radius, which became a serious inconvenience on the narrow streets of European cities.

Another peculiarity of the M2 and its descendants was the construction of their tracks: instead of using metal track links like tanks, they had a molded rubber track over steel cabling. This made the track much lighter, but also more vulnerable. If a tank track ran over a mine and damaged a few links, those could be replaced with spares on hand; if a halftrack suffered similar damage, the entire track had to be taken off and a new one put in place.
 
Production of the M2 began in 1940, but a new vehicle, specifically designed as a troop carrier, was following hot on its heels: the M3 half-track. The M3 was similar to the M2 but larger, capable of carrying a 12-man rifle squad (including the driver, who would dismount from the vehicle and fight alongside his comrades).  Like its predecessor, the M3 was lightly armored – sufficiently enough to offer some protection against shrapnel and small arms, but not well enough to keep the passengers safe from a heavy machine gun. The thin armor, as well as the complete lack of top protection, drew criticism from the vehicle’s users early on. General George S. Patton (Read our earlier article – The wars of George S. Patton) offered some criticism with his usual outspoken wit: "The two most dangerous weapons the Germans have are our own armored halftrack and jeep. The halftrack because the boys in it go all heroic, thinking they are in a tank. The jeep because we have so many God-awful drivers."

Patton was quite correct about one thing: the M3 was not supposed to be a fighting vehicle. It was more of a “battlefield taxi” that the passengers would ride until they got close enough to the action, but then they were expected to dismount and fight on foot. A more reserved commentary by General Bradley noted that “[the M3’s] bad name resulted from the inexperience of our troops who attempted to use it for too many things." At any rate, the half-track’s initial unpopularity with the infantry earned it the nicknamed “Purple Heart box.”
 
It should be noted that the M3’s German counterpart, the Sd.Kfz. 251, was designed as a fighting platform, with troops capable of engaging the enemy from onboard. This, along with its ability to turn while stationary (like a tank, simultaneously moving one track forward and the other in reverse), made it a more modern design than the M3, but one which the Germans couldn’t hope to produce in similar numbers.

American half-tracks first saw action in the Philippines against invading Japanese troops, and went on to serve in practically every theater of the war: the rest of the Pacific, North Africa, Sicily, Italy, and Western Europe. Lend-Lease half-tracks also saw combat with the Red Army on the Eastern Front. The M3’s basic armament was either a .30 caliber (Read our earlier article – The .30 cal Browning) or a .50 caliber machine gun (Read our earlier article – The Browning .50 cal), but the adaptable vehicle had numerous variations with other weapons.

A typical Armored Rifle Company from 1943 onward used no fewer than 21 half-tracks (alongside other vehicles). The headquarters had a command half-track with a .50 cal and additional radio equipment, a half-track with a .50 cal gun used by the maintenance section, and an unarmed ambulance half-track. Each of the three Rifle Platoons in the company had five vehicles: a Platoon Headquarters half-track armed with a .50 cal carrying the platoon commander and a full rifle squad; three with a .30 cal machine gun (two carrying a rifle squad each and one a mortar squad), and finally one carrying a light machine gun squad armed with a .50 cal and two .30 cals. Additionally, the company had an Anti-Tank Platoon with three half-tracks, each armed with a Browning machine gun of some caliber and towing a 57mm anti-tank gun. 

The M3 proved to be a useful and ubiquitous platform for other weapons as well. Here are some of the most important versions:
 
M5 half-track. The M3 was built by the Diamond T, Autocar and White Motor Companies. International Harvester could and did produce almost identical half-tracks, but with some changes due to different manufacturing equipment. The M5 was very similar to the M3, but with a different engine that was slower and had a shorter range. It also had slightly thicker armor, but of inferior quality that offered less protection.

Most M5s were sent to Britain, France and the Soviet Union as Lend-Lease vehicles. Britain didn’t particularly need an American troop personnel carrier as they already had their own Universal Carrier, so they mainly used their M5s to tow artillery pieces.

The M3A1 and M5A1 were upgraded versions of the M3 and M5. They were very similar to their predecessors, but with gradual improvements to the engine and the drivetrain. They also had more stowage capacity, which the originals lacked somewhat, forcing troops to hang some of their gear on the outside of their ride. One visible difference between these new versions and the old ones was that the old pintle mount for the machine gun was replaced with a ring mount, while additional pintle mounts were added so the vehicle could carry extra .30 caliber machine guns. All M3s were eventually upgraded to the M3A1 over the course of the war.

The M9 was an M5 with some modifications to make it more similar to the older M2. The modifications included different stowage arrangement, radios that could be used from the inside, and a rear door for soldiers to dismount through.
 
Hitler’s invasion of Poland in 1939 and France in 1940 showed the world the importance of self-propelled artillery that could keep up with tanks. The U.S. had no such vehicles at the time, and had to scramble for a stopgap measure: take a transport vehicle that can keep up with tanks off-road and put a gun on it. The M3 GMC (Gun Motor Carriage) was exactly this kind of makeshift weapon, and one of America’s first tank destroyers: an M3 with a 75mm field gun in the back.  The M3 GMC wasn’t exactly a very good vehicle: its minimal armor was useless against tanks, and the gun, not being placed in a turret, only had limited traverse, so the entire vehicle had to be pointed toward the enemy. It performed acceptably against Japanese light and medium tanks in the Pacific, and with mixed success against German forces in North Africa. At the Battle of El Guettar, GMCs took out 30 German tanks, possibly including two Tigers, with 21 half-tracks lost in exchange. The GMCs went on to serve in the Pacific and saw some action in Sicily, but were quickly replaced by the M10, a proper tank destroyer.

A variety of other guns was also fitted on M3s, including different types of Howitzers or a mortar, which could be either fired from inside the vehicle or placed on the ground and used the traditional way.

Another avenue of development came with the addition of anti-air weapons to a half-track to allow it to protect ground troops against low-flying aircraft such as dive bombers or strafing fighters. The M13 and M14 MGMC (Multiple Gun Motor Carriage) were an M3 and an M5, respectively, equipped with a mount that held two .50 caliber Browning machine guns. A similar but more powerful and famous design was the M16 MGMC, nicknamed the “Meat Chopper.” The M16 doubled the number of .50 cals to four, each fed ammunition from a descriptively nicknamed “tombstone” magazine, giving it impressive firepower against air targets and also making it a fearsome anti-infantry weapon.  It went on to serve in the Korean War, mainly as a ground support vehicle, since aircraft have become too fast to be hit by machine guns by then.

Another, lesser-known but very interesting variation was the M15 and its improved version, the M15A1 MGMC. The M15 surrounded the gunners with a metal box for extra protection, and had an unusual weapons combination on its mount: two .50 cal M2 Browning machine guns and a single 37mm anti-aircraft autocannon. This allowed the crew to combine the higher volume of individually less destructive machine gun rounds with the slower-firing but deadlier 37mm shells. There were reports of German aircraft flying close enough to attack the “lightly armed” vehicle only to get a fatal surprise when the third, heavier gun opened up. The machine guns could also be loaded with tracer rounds that helped in aiming the 37mm.

The “M15 Special” was an Australian experiment in which an even heavier anti-air cannon, the mighty 40mm Bofors gun, was placed on the M3. The vehicle ended up being used as a direct-fire support vehicle, rather than as a proper anti-air weapon, and was the only one of some half dozen experiments that managed to put the Bofors on a half-track; in all other cases, either the gun’s recoil was too powerful, or its mounting too heavy for the vehicle.

World War II was the golden age for the M3 half-track family (and the half-tracks of other nations), but their sun began to set soon afterward. Various M3 versions saw action in the Korean War, and some militaries, such as the Israeli Defense Forces, continued to use them well into the Cold War, but major militaries abandoned the idea. The functional niche between wheeled and tracked vehicles was growing ever narrower, and no longer warranted a compromise solution. Even during World War II, vehicles like the Universal Carrier and the Kangaroo armored personnel carrier proved that all-tracked vehicles are quite capable of ferrying around soldiers. Meanwhile, 6- and 8-wheeled German heavy armored cars proved that wheeled vehicles had adequate off-road capability as long as they used all-wheel drives. And thus, the M3 half-track and its large family largely remains a relic of World War II. You can still see some of them on our tours: on display in museums, or even in running order either at D-Day anniversary celebrations in Normandy or during Battle of the Bulge anniversaries in Bastogne.

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