Categories
WW2 US Tank Destroyers

90mm GMC M36 Jackson

ww2 US tanks USA (1943) Tank Hunter – 1,772 built

The ultimate American tank hunter of WW2

The M36 Jackson was the last dedicated American tank hunter of the war. After the early, soon obsolete M10 Wolverine and the superfast M18 Hellcat, the US Army needed a more powerful gun and better armored vehicle to hunt down the latest developments in German tanks, including the Panther and Tigers. Indeed, in September 1942, it was already foreseen that the standard 75 mm (3 in) M7 gun of the M10 was only efficient at short range (500 m) against the enemy vehicles. Engineers were tasked with devising a new 90 mm (3.54 in) gun, which became the M3 gun, to engage German tanks on equal terms considering range. This gun was also used by the M26 Pershing.
M10A1 GMC in trials, 1943. The T71 was developed on this hull and chassis
M10A1 GMC in trials, 1943. The T71 was developed on this hull and chassis.
The need for a better armed tank hunter was confirmed, at a high cost, in the battle of Kasserine pass and later in multiple engagements in Sicily and Italy. The new tank equipped with this gun was designed quickly on the basis of the M10 tank destroyer. At first, the T53 sought a dual AA/AT rôle, but was eventually canceled.
The T71, which would become the M36, was completed in March 1943. However, due to multiple issues, the production only started mid-1944 and the first deliveries came in September 1944, two years after the idea was first proposed. This new tank hunter was known by the soldiers as “Jackson” in reference to the Confederate general of the Civil War Stonewall Jackson, or “Slugger”. Officially, it was named “M36 tank destroyer” or “90 mm Gun Motor Carriage M36” by the ordnance and US Army at large. It proved itself vastly superior to the M10, and was arguably the finest American tank hunter of World War Two, with a long postwar career.
T71 GMC pilot prototype in 1943
T71 GMC pilot prototype in 1943

Development (1943-44)

The first M36 prototype was completed in March 1943. It was characterized by a new turret mounting the 90 mm M3 gun on a standard M10 chassis. The prototype designated T71 Gun Motor Carriage and passed all tests with success, proving lighter and thus more agile than the regular Sherman M4A3. An order for 500 was issued. Upon standardization, the designation was changed to “90 mm Gun Motor Carriage M36” in June 1944. These were produced by the Fisher Tank Division (General Motors), Massey Harris Co., American Locomotive Co. and Montreal Locomotive Works (chassis) and hulls by the Grand Blanc Arsenal. The M36 was based on the upgraded M10A1 Wolverine hull, whereas the B2 was based on the regular M10 chassis/M4A3 diesel.
M36B2 at Danbury - side view
M36B2 at Danbury, – side view

Design

Like all US tank destroyers, the turret was open-topped to save weight and provide better peripheral observation. However, the turret design was not a simple repeat of the sloped plates of the M10 but rather a thick casting with front and side slopes and a backwards recline. A bustle acting as turret basket was welded on this casting to the rear, providing extra ammo storage (11 rounds) as well as acting as a counterweight for the M3 main gun (47 rounds, HE and AP). The main secondary armament, the usual dual purpose “Ma Deuce” cal.50 (12.7 mm) Browning M2 heavy machine gun was installed on a pintle mount on this bustle, but there was no coaxial MG. The B1 variant introduced a secondary Browning M1919 cal.30 in the hull. Postwar modifications included a folding armored roof kit to provide some protection against shrapnel, but also later fitting of a hull ball mount Browning cal.30 machine gun on the co-driver’s position and the new M3A1 gun.
GMC 6046 engine
GMC 6046 engine
The chassis was basically the same as the M10, with a Ford GAA V-8 gasoline 450 hp (336 kW) which gave a 15.5 hp/ton ratio, coupled with a Synchromesh gearbox with 5 forward and 1 reverse ratio. With 192 gallons of gasoline, this gave a 240 km (150 mi) range on roads with a top speed on flat ground of up to 48 km/h (30 mph). The running gear was comprised of three bogies with Vertical Volute Spring Suspension (VVSS), 12 rubberized roadwheels, with front idlers and rear drive sprockets. Hull protection counted on 13 mm thick add-on bolted armored panels like the M10 and ranged from 9 mm (035 in) to 108 mm (4.25 in) on the gun mantlet and front hull glacis plate. In detail these figures were:
Glacis front hull 38–108 mm / 0–56 °
Side (hull) 19–25 mm / 0–38 °
Rear (hull) 19–25 mm / 0–38 °
Top (hull) 10–19 mm / 90 °
Bottom (hull) 13 mm / 90 °
Front (turret) 76 mm /0 °
Sides (turret) 31,8 mm / 5 °
Rear (turret) 44,5–130 mm / 0 °
Top (turret) 0–25 mm /90 °

Variants

M36 (standard): 3″ GMC M10A1 hull (M4A3 chassis, 1,298 produced/converted)
M36B1: Conversion on M4A3 hull and chassis. (187).
M36B2: Conversion on M4A2 chassis (same hull as M10) with a twin 6-71 arrangement GM 6046 diesel (287).
M36B2 GMC at Danbury
M36B2 GMC at Danbury

The M36 in action

Although fielded much earlier for training, the first M36 in organic tank hunter units, in accordance with the US TD doctrine, arrived in September 1944 on the European Theater of Operations (also at the insistence of Eisenhower that regularly had reports about the Panther). It showed itself a formidable opponent for German tanks, largely on par with the British Firefly (also based on the Sherman). In addition, between October and December 1944, 187 conversions of standard Medium Tank M4A3 hulls into M36s were performed at the Grand Blanc Arsenal. These were designated M36B1 and rushed to the European Theater of Operations to combat alongside regular M36s. Later in the war, M4A2 (diesel versions) were also converted as B2s. The latter, in addition to their roof-mounted add-on armor folding panels, also had an upgraded M3 main gun with a muzzle brake.
The M36 was capable of nailing down any known German tanks at reasonable range (1,000 to 2,500 m depending of the armor thickness to deal with). Its gun left little smoke when firing. It was liked by its crew, but because of its high demand, fell rapidly in short supply: Only 1,300 M36s were manufactured in all, of which perhaps 400 were available in December 1944. However, like other US tanks hunters, it was still vulnerable to shell fragments and snipers due to its open-top turret. Field modifications, like for the M10, were hastily performed by the crews, welding additional roof iron plating. Later on, a kit was developed to protect against shrapnel, made of folding panels adopted by the M36B2, generalized after the war. When entirely closed there was a gap above the turret allowing the crew to still have a good peripheral vision. The other backsides was the choice of its Sherman chassis with a high transmission tunnel which made for a conspicuous target at 10 feet tall.
In an engagement with a German Panther tank at 1500 yards, an M36 of the 776th TD Battalion was able to penetrate the turret armor which became the commonplace preferred target, along with the sides, rather than the glacis. Tigers were harder to handle and needed to be engaged at smaller ranges. Mediums were relatively easier prey until the end of the war. The King Tiger was a slight problem, but it could still be destroyed with the proper range, angle and ammo. As an example, near Freihaldenhoven in December 1944, an M36 from the 702nd TD Battalion knocked out a King Tiger at 1,000 yards by a side shot in the turret. Panthers were generally knocked out at 1,500 yards.

M36 GMC, December 1944, en route for the battle of the Bulge
M36 GMC, December 1944, en route to the battle of the BulgeDuring the Battle of the Bulge, the 7th AD was engaged, with its M36s, at St Vith with success, despite artillery shelling and wood splinters, or the presence of snipers in these woody areas. M18 Hellcats (such as those of the 705th TD Bat.) also did wonders and all combined American TDs destroyed 306 German tanks during this campaign. It should be noted there were still numerous towed battalions at that time, which suffered the highest losses. The roof vulnerability of the M36 did much to rush out the arrival of the M26 Pershing, similarly armed. In addition, specialized semi-independent TD battalions ceased to be used and the M36s (the TD doctrine had been discredited meanwhile) were now operated within mechanized groups, fighting alongside infantry.Indeed at the time of the attack of the Siegfried lines, the M36 was used in close proximity of the troops and proved quite useful with HE shells against German bunkers. A postwar study alleged that the 39 TDs battalions knocked out no less than 1,344 German tanks and assault tanksuntil the end of the war, while the best battalion claimed 105 Germans tanks and TDs. The average kill count per battalion was 34 enemy tanks/assault guns, but also 17 pillboxes, 16 MG nests, and 24 vehicles.When the M36s and M18s started to arrive in force in Europe, M10 were gradually reassigned to less sensitive sectors and sent to the Pacific. They were first used at Kwajalein, in February 1944. No less than seven TD battalions operated there with M10s and M18s, but no M36s. Some M36s did eventually serve in Asia, in French use, at first with the Free Forces, then after the war with more US supplied vehicles arriving in Indochina.

Postwar operators

The M36’s main gun was still a match for the first modern MBTs. However, as most US WWII tanks, it was used in the Korean War and proved well capable of destroying the T-34/85s fielded by the North Koreans. They were judged as faster and more agile than the M26 but still much better armed than lighter tanks like the M24 and, some years after, the M41. The hull ball-mounted machine gun on the co-driver’s side was a postwar addition to all surviving M36s, and later an M3A1 90 mm gun (shared with the M46 Patton) was mounted instead of the 90 mm M3. This new gun can be recognized by its muzzle brake and bore evacuator. M36s were prioritized for the Military Assistance Program transfer towards South Korea over the more modern but similarly armed M26/M46. 110 M36s along with a few M10 TDs were transferred to the South Korean Army, serving until 1959. Many also found their way into other armies, although in limited numbers.
In Asia, after South Korea, the Army of the Republic of China acquired just 8 ex-French M36s in 1955, stationed on Kinmen Island until April 2001. At that time, two were still registered for training in Lieyu. The French also acquired some postwar, which were found in action in the 1st Indo-China war. Indeed, against the threat of a possible Chinese intervention and use of the IS-2 heavy tank, a Panther was first tested without success, and M36B2s were sent instead with the RBCEO and custom modifications (roof plates and additional .30 cal) in 1951. As the threat never materialized, these were used for infantry support until 1956.
Italy also received some postwar, deactivated in the 1960s. Another European operator was Yugoslavia (postwar). By the 1970s, these were modernized with a T-55 Soviet-made 500 hp diesel. After the partition of the country, existing M36s were passed to the successor states and saw heavy action, in particular in the Croatian War of Independence (1991–1995, withdrawn in 1995) but also with the Serbian forces in Bosnia, Croatia, and Kosovo War as decoys for NATO air strikes.
M36s were also purchased after the partition of India, seeing action on both sides in the Indo-Pakistani War of 1965. The Indian 25th and 11th cavalry units used these as mediums due to their mobility. However, the Indians claimed 12 Pakistani M36B2s in the battle of Asal Uttar alone, and the remainder were decommissioned before the battle of 1971.
ROCA (Republic of China Army) M36 on display at the Chengkungling museum.
ROCA (Republic of China Army) M36 on display at the Chengkungling museum.
Iran was also provided M36s before the revolution of 1979, and saw action in the Iran-Iraq war. The Iraqis managed to capture a few M36s and M36B1s which also were deployed in the 1991 Gulf War. Other operators included the Philippine Army (until the 1960s) and Turkey (222 donated, now long deactivated). Many surviving vehicles were maintained in running conditions and some found their ways into museums and private collections around the world.
South Korean M36B2 or modernized M36, South Korean Army (Seoul Museum, Flickr)
South Korean M36B2 or modernized M36, South Korean Army (Seoul Museum, Flickr)

Sources

The M36 on Wikipedia
Tankdestroyer.net
US Tanks destroyers in Combat – Armor at War series – Steven J. Zaloga

M36 specifications

Dimensions (L x W x H) 5.88 without gun x 3.04 x 2.79 m (19’3″ x 9’11” x 9’2″)
Total weight, battle ready 29 tonnes
Crew 4 (driver, commander, gunner, loader)
Propulsion Ford GAA V-8, gasoline, 450 hp, 15.5 hp/t
Suspension VVSS
Speed (road) 48 km/h (30 mph)
Range 240 km (150 mi) on flat
Armament 90 mm M3 (47 rounds)
cal.50 AA machine gun(1000 rounds)
Armor 8 mm to 108 mm front (0.31-4.25 in)
Total production 1772 in 1945

Rare restored footage: TD Boot Cam color 1943

Gallery

Various references from the web, for modellers inspiration: M36 and M36B1 and B2 from Yugoslavia, Croatia or Bosnia, Serbia, Taiwan, Iran, and Iraq.
Various references from the web, for modeller inspiration: M36, M36B1 and B2 from Yugoslavia, Croatia or Bosnia, Serbia, Taiwan, Iran, and Iraq.

M36 Jackson, early type in trials in UK, summer 1944.
M36 Jackson, early type in trials in UK, summer 1944. Notice the muzzle-less gun and absent add-on side armour plates
Regular M36 Jackson in Belgium, December 1944.
Regular M36 Jackson in Belgium, December 1944.
M36 Tank Destroyer camouflaged in a winter livery, west bank of the Rhine, January 1945.
M36 Tank Destroyer camouflaged in a winter livery, west bank of the Rhine, January 1945.
Mid-production M36 Pork Shop, U.S. Army, 2nd Cavalry, Third Army, Germany, March 1945.
Mid-production M36 “Pork Shop”, U.S. Army, 2nd Cavalry, Third Army, Germany, March 1945.
Late Gun Motor Carriage M36, Belgium, December 1944.
Late Gun Motor Carriage M36, Belgium, December 1944.
M36B1 in Germany, March-April 1945.
M36B1 in Germany, March-April 1945.
French M36B2 Puma of the Régiment Blindé Colonial d'Extrême Orient, Tonkin, 1951.
French M36B2 “Puma” of the Régiment Blindé Colonial d’Extrême Orient, Tonkin, 1951. Notice the extra cal.30.
Iraqi M36B1 (ex. Iranian), 1991 Gulf War
Iraqi M36B1 (ex. Iranian), 1991 Gulf War
Croatian M36 077
Croatian M36 077 “Topovnjaca”, War of Independence, Dubrovnik brigade, 1993.

Seek Strike Destroy – U.S. Tank Destroyers Shirt

Seek Strike Destroy – U.S. Tank Destroyers Shirt

Seek, Strike, and Destroy your opponents with this Hellcat of a U.S. tank destroyer! A portion of the proceeds from this purchase will support Tank Encyclopedia, a military history research project. Buy this T-Shirt on Gunji Graphics!


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WW2 US Tank Destroyers

76.2mm GMC M18 Hellcat

USA (1944) Tank Hunter- about 2,507 built

Historical Background

As the United States army entered World War II, it drew certain conclusions from Germany’s quick victories over Poland and France. One was that a highly mobile tank destroyer force needed to be held in reserve to deal with sudden Panzer breakthroughs as they occurred, rather than keep anti-tank forces at the front.
Therefore, anti-tank elements were removed from infantry divisions to form independent battalions, which were initially equipped with a number of improvised mobile tank destroyers, the M3 half-track mounting a 75 mm (2.95 in) gun, and the GMC M6, a truck with a 37 mm (1.46 in) gun.
Restored M18 GMC Hellcat tank destroyer at the Military Odyssey event in southern England.
Restored M18 GMC Hellcat tank destroyer at the Military Odyssey event in southern England.
Once Operation Torch provided battlefield experience for the army to evaluate, it became apparent that more powerful tank destroyers would be needed. First of the more powerful weapons was the M10, built on the chassis of an M4 armed with a 76.2 mm (3 in) gun. However, the M10 was still insufficient, so an order went out for a tank destroyer designed from the ground up to hunt and destroy tanks. This vehicle would become the M18 Hellcat.
In December 1941, the Ordnance Corps issued a requirement for a fast tank destroyer using torsion bar suspension, a Wright/Continental R-975 engine, and a 37 mm (1.46 in) gun. This became the T42 37 mm (1.46 in) Gun Motor Carriage. The army then changed their request to a vehicle mounting a 57 mm (2.24 in) gun, thus the designation changed to the T49 57 mm Gun Motor Carriage. Yet another change, requesting a 75 mm (2.95 in) gun, led to the T67 Gun Motor Carriage, of which one was built from a T49 chassis.
Finally, the T70 76 mm Gun Motor Carriage emerged and would become the M18 Hellcat. It was designed by Harley Earl at Buick. Tests on an oval track, as well as a specially designed bumpy track, demonstrated that the lightly armored vehicle could achieve high speeds. Production of the M18 started on January 7th, 1943, when 1,000 units were ordered.

Design

Speed and agility were the hallmarks of this particular tank destroyer; these qualities came about from using a powerful engine and by keeping armored protection to a minimum. As was the case with other tank destroyers used by the United States, the M18 had an open turret, which left the crew vulnerable to snipers, grenades, and shrapnel.
Rarely was the high speed of the Hellcat fully used in combat, but the ability to outflank German tanks, for side and rear shots, did benefit the crews against the heavily armored Panther and Tiger tanks. Ease of maintenance came from the engine being mounted on steel rollers, which permitted quick removal and replacement. The transmission was also easily accessed in this manner. The 76 mm (3 in) gun soon proved to be not as effective as hoped against German armor, although a limited supply of high-velocity armor piercing ammunition did compensate to some extent.
The crew comprised five members, the commander in the turret left rear, gunner in the turret left front, loader in the turret right, driver in the left front, and assistant driver in the hull right front. The armor consisted of rolled and cast homogeneous steel, as follows: Gun shield .75 inch (1.9 cm) from 0-60 degrees; Front (cast) 1 inch (2.5 cm) 23 degrees; Sides .5 inch (1.3 cm) 20 degrees; Rear .5 inch (1.3 cm) 9 degrees; Top (none); and floor 0.25 in (6 mm).
The main armament was a 76 mm (3 in) M1A1, M1A1C or M1A2 gun with 45 rounds. It had a 360-degree manual and hydraulic traverse at 24 degrees/second, +20 degrees to -10 degrees of elevation/depression. The secondary armament comprised a .50 (12.7 in) caliber M2HB machine gun in a ring mount (800 rounds), rotating 360 degrees, with manual traverse.

Production

In July of 1943, the Hellcat went into production at the Buick plant in Flint Michigan. Although Buick was contracted to build 8,986 Hellcats for the US army and Lend-Lease recipients, only a total of 2,507 vehicles were produced, with production ceasing in October 1944.

Variants

There were a number of variants tested using the chassis of the Hellcat. The T86 and T86E1 amphibious tank destroyers, as well as the T87 105 mm (4.13 in) amphibious Howitzer Motor Carriage, the T88 105 mm (4.13 in) Howitzer Motor Carriage and the Super Hellcat mounting the turret from the M36 turret were all tested, but none proceeded to production before war’s end.
The only variant of the M18 to see production and combat was the T41/M39 armored utility vehicle, used as a turretless personnel or cargo carrier and as a gun tractor. M39s saw service in both World War II and Korea, before being declared obsolete on February 14th, 1957. A prototype of the M39 was tried as a flame thrower tank, the T65. It did not go into production.

Active service

Although some Hellcats went to China to fight the Japanese army, they were primarily used in support of infantry, as Japanese armor was scarce and of poor quality. Two battalions of tank destroyers did see service in the invasion of the Philippines using Hellcats. Starting with Anzio in Italy, M18s saw action in Italy and Northwest Europe.
The following tank battalions used the M18 during part or all of their service: 602nd battalion 9\1944, 603rd 8\1944, 609th 9\1944, 612th 1\1945, 637th 1\1945 (Pacific), 638th 11\1944, 643rd 2-3\1945, 648th 5\1945?, 656th 2\1945, 661st 2\1945, 704th 7\1944, 705th 7\1944, 801st 4\1945, 805th 6\1944, 807th 4\1945, 809th 2\1945-4\1945, 811th 11\1944, 817th 4\1945, 820th 4\1945, 822nd 4\1945, 824th 3\1945, 827th 12\1944. Note: The dates are for when the unit received the Hellcat.
According to the army’s “Seek, Strike, Destroy” doctrine, these battalions were to be kept under the control of upper echelon headquarters, in order to respond quickly to mass Panzer attacks. However, since the Germans almost never employed their tanks in this manner, the battalions ended up parceled out to infantry divisions, where they provided direct fire support, blasting pill boxes and other fortifications, or in indirect fire roles interdicting German movement. Not designed for these roles, the M18 nevertheless did excellent work supplementing the artillery of these infantry divisions.
Throughout the long campaign in Italy, then through France and the Low Countries, the tank destroyer units had a number of moments to shine as tank destroyers; at Arracourt, in France, on September 19th 1944, the 704th TD battalion in support of the 4th Armored Division destroyed 15 tanks of the German 113th Panzer brigade while in a dense fog; during the Ardennes offensive on December 19th-20th 1944, 4 Hellcats of the 705th TD battalion supported an attack on the 2nd Panzer division.
This spoiling attack slowed down the German attempt to seize Bastogne until the Americans could organize their defenses. In addition to serving with the United States army, the Hellcat also served with the armies of Taiwan, West Germany, and Yugoslavia (until the 1990’s).
An article by Tim Cox

Sources & Links about the M18 Hellcat

tankdestroyer.net
AFV Data Base
The Pacific War Online
“Seek, Strike, and Destroy: US Army Tank Destroyer Doctrine in World War II.” Dr. Christopher R. Gabel; Combat Studies Institute, US Army Command and General Staff College Fort Leavenworth Kansas September 1985
Buick M18 Hellcat Tank Destroyer First Drive – Four Wheeler
M18 76mm Gun Motor Carriage Hellcat – History of War
M18 Gun Motor Carriage (Hellcat) – Tank Destroyer/Gun Motor Carriage – History, Specs and Pictures – Military Factory
UNITED STATES ARMY IN WORLD WAR II, The European Theater of Operations – “THE LORRAINE CAMPAIGN” Hugh M. Cole

76mm Gun Motor Carriage M18 specifications

Dimensions
(L-W-H)
19ft 9″ x 9ft 11in x 7’3″
(6.01m x 3.03m x 2.32m)
Total weight, battle ready 18 tons (39,000 lbs)
Crew 5 (driver, co-driver, commander, gunner, loader)
Propulsion Continental radial R-975-C4 9 cyl., gas. 900T Torqmatic transmission
Top speed 50 mph (80 km/h) road
18 mph (29 km/h) off-road
Range (road) 105/160 mi (160 km at cruising speed)
Armament 76 mm (3 in) gun M1A1/M1A1C/M1A2, 45 rounds
Cal.50 (12.7 mm) Browning M2HB, 800 rounds
Armor From 1 inch (glacis) to 0.2 in (floor) (25 mm to 5 mm)

Camouflaged Hellcat at Anzio, May 1944.
Camouflaged Hellcat at Anzio, May 1944. The camouflage scheme is deduced from a picture from the front. Notice the early gun without muzzle break.

M18 Hellcat in Italy, 1944.
M18 Hellcat in Italy, 1944.

M18 Amazin Grace from an unknown US Army unit in France, 1944.
M18 “Amazin Grace” from an unknown US Army unit in France, 1944.

Hellcat from the 805th Tank Destroyer Battalion in Italy, 1944.
Hellcat from the 805th Tank Destroyer Battalion in Italy, 1944.

M18 Hellcat, Battle of the Bulge, winter 1944-45.
M18 Hellcat, Battle of the Bulge, winter 1944-45.

Super Hellcat in 1944, with an olive green/dark brown camouflage
“Super Hellcat” in 1944, with an olive green/dark brown camouflage

M39 Carrier in Korea, 1952.
M39 Carrier in Korea, 1952.

Hellcat from the 249 MAC Division, Republic of China, 1980s.
Hellcat from the 249 MAC Division, Republic of China, 1980s.

Bosnian Serb M18 Hellcat in 1995.
Bosnian Serb M18 Hellcat in 1995.

Gallery

An M18 Hellcat at a reenactment in 2008Hellcat at Wiesloch, Germany, 04/01/1945.M39 of a Medical unit in KoreaM39 Carrier in Korea, 1952

Seek Strike Destroy – U.S. Tank Destroyers Shirt

Seek Strike Destroy – U.S. Tank Destroyers Shirt

Seek, Strike, and Destroy your opponents with this Hellcat of a U.S. tank destroyer! A portion of the proceeds from this purchase will support Tank Encyclopedia, a military history research project. Buy this T-Shirt on Gunji Graphics!


Categories
WW2 US Tank Destroyers

3in GMC M10 Wolverine

USA (1942) Tank hunter- 6,706 built

Early development

After their first encounters with the Soviet KV-1s and T-34s, the German Army was poised to revise its tank design and take immediate action to bolster their firepower and protection. On one hand, they up-gunned the Panzer IV, which became the staple of the German tank forces, and, on the other, rearmed the StuG III as a tank-hunter.
They also converted several other chassis for this role and pressed many new specialized models into action. This had some effects on Allied forces, and in particular the US Army Corps, which sought to use a standard tracked chassis to create a proper tank hunter of its own.

Until then, one of the vehicles used as such was the T12 GMC, a conversion of the M3 half-track with a shielded M1897A4 75 mm (2.95 in) gun. It lacked protection, mobility and had the limitations of an SPG.
The only purpose-built vehicle in service then was the M6 GMC, a Ford truck with a standard 37 mm (1.46 in) gun mounted in the rear bay. 5380 were built in 1942, but it was not a success, and it was considered obsolete by 1943. In 1942, the head of staff was actively searching for a fully tracked tank hunter, using the M4 chassis.

Of note is that neither the British nor the US armies seem to have ever called the GMC M10 the “Wolverine”. It is possible that this name was given by the Canadians at some point, but it is also possible it is a post-war invention. The “Wolverine” name was then popularized by model kit companies along with the World of Tanks and Warthunder video games.

Doctrine

A tracked tank-hunter was already improvised and tested on the M3 Lee chassis. A later conversion of this vehicle became the 105 mm Howitzer Motor Carriage M7, better known as the “Priest”. For the ordnance top brass, thinking of maintenance, shipping and training, using the M4 chassis for a tank hunter was not only feasible but also highly desirable. The biggest supporter of this concept was General Lesley McNair, the head of the ground forces.

This also led to the creation of the Tank Destroyer Force, a dedicated reserve unit embracing a new doctrine. These vehicles would be held in reserve until an enemy tank breakthrough and were then deployed quickly, using fast maneuvers and firepower to destroy the opposing vehicles. This resulted in putting emphasis on speed and firepower, with some sacrifice in protection.

Design of the M10 GMC

Based on these requirements, the first prototype was based on the M3 chassis, and later the production was swapped to the M4 standardized chassis. By these means, every component of the drivetrain, complete with bogies with VVSS, roadwheels, idlers and drive sprockets, return rollers and tracks, and the internal arrangement were kept the same. The engine was specific to this vehicle, made of twin GM 6-71s diesels mated on a common crankshaft and specific transmission. The armor and turret were completely new.

The prototype 3-inch Gun Motor Carriage T35 was given a standard 3-inch (76.2 mm) M7 gun and a circular open-top turret already produced for the early production M4A1 (later replaced by conventional turrets on these). The second prototype, T35E1, used the M4A2 chassis and had a new pentagonal turret with flat, sloped sides, frontal beak and inverted rear slope. The mantlet was then wrapped around this “beak”.

The sides received well-sloped flat armor plates with a “>” section, held in place, like the turret plates, by massive nuts. Various handles were welded on these for fastening external storage. Due to the lightness of the turret and the frontal weight of the gun, two large counterweights were added to the rear basket. A secondary cal.50 (12.7 mm) machine-gun was mounted on top, both for AA and ground defense. The prototype was further refined and ended as the 3-inch Gun Motor Carriage M10, earning the go ahead for production in mid-1942.

The M7 gun fired M79 AP shots that could penetrate 3 inches (76 mm) of 30° sloped armor at 1,000 yards (915 m). The Armor Piercing Capped Ballistic Cap (APCBC) M62 was introduced later, as well as the High Velocity Armor Piercing (HVAP) M93 shot and Armor Piercing High Explosive (APHE) shells. The vehicle could carry 54 rounds. However, this naval-derived round had a small charge, lacked initial velocity and often failed to penetrate standard 50-70 mm (1.97-2.76 in) armor.

Production, operators and variants

Production was assumed at General Motors Fisher Tank Arsenal in Grand Blanc, Michigan (4,993 M10s and 375 M10A1s from September 1942 to December 1943). The Ford plants produced another 1,028 vehicles of the M10A1 variant (October 1942 – September 1943), and Fisher produced a further 300 turretless M10A1s used as artillery tractors, later converted as M36 Jacksons. The total number of units built reached 6,706 in December 1943.

The M10A1

The 1700 M10A1s received a gasoline Ford GAA engine and were based on the M4A3 chassis. The last 300 vehicles received the new M1 76 mm (3 in) gun, which had better muzzle velocity and could fire heavier ammunition. By 1944, the M10 had started to lose the edge against the Panthers and Tigers, until HVAP rounds were supplied, and even then they had to find weak points and maneuver around the German tanks to be effective.

Full-Track Prime Mover M35

Turretless M10A1s built by Fischer were used as artillery tractors and improvised APCs for the gun crews. 300 were delivered in total by the end of 1943.

Chinese M10 Self-Propelled Howitzers

Some M10s, which had been previously demilitarized, were transferred to Republican China (ROC). In 1949, one was rearmed with a modified Japanese 105 mm (4.13 in) howitzer. It was also fitted with a light, armored permanent turret roof dotted with observation hatches and an access door. A machine gun port was also made into the bow hull. This successful conversion was followed by sixteen others.

In British service

Several hundred were pressed into British service under Lend-Lease, called (Gun) 3 inch Self Propelled (3 in SP). These were assimilated as SPGs, operated by Royal Artillery units, and saw service in 1944 in Italy and France (especially with the Canadians and Poles). The tactical organization was four-battery regiments, with some alternating two towed 17-pdr batteries and two 3in SP batteries, later rearmed with the famed 17 pounder (76.2 mm/3 in) gun.
These conversions, into the new 17pdr SP “Achilles” tank hunter, counted about 1100 machines, done by the Royal Arsenal at Woolwich. It was, in mid-1944, the second most common British/Commonwealth tank hunter after the Firefly. Sub-types were the Diesel/Gasoline powered Ic and IIc. The Canadians also derived a single prototype of their Ram tank into the M10 configuration in 1942, as the 3in SP Wolverine, for a projected production. Some Achilles were later used by the Israeli in the 1956 and 1967 wars.

In Russian service

The Red Army received only 54 M10s, but their action is unrecorded, as well as the crew opinions on these. There is no doubt that the open-top turret was not appreciated in winter, and both the lack of protection and firepower did not contribute to their popularity.

In Free French service

The 1st Free French Army led by General De Lattre received dozens of M10s, operated in similar lines as US tank hunter units. They soldiered well from the French Riviera until the liberation of Paris in August 1944, when a single M10 named “Sirocco” disabled a Panther in Place de la Concorde. They also saw action on the French-German border around Strasbourg and in southern Germany, and Indochina after the war.

The “Wolverine” in action

In US service, the first engagements came in early 1943, in Tunisia. Although in short supply, they proved quite up to the task against any German tanks, including the latest evolution of the Panzer IV. On flat ground, they were fast enough and able to maneuver around enemy tanks with ease. Their open-top turret was a problem in specific urban and heavily forested environments, and also because of shrapnel and grenades.
But the crews loved it anyway, because observation was easier, both to spot enemy tanks and to fire, they could communicate more easily with the infantry, and in case their tank was disabled, they could escape quite quickly, compared to the Sherman and other Allied tanks. There was a waterproof canvas, which could be deployed on top of this open space. In general, the open-top turret was not seen as a problem since US Army doctrine of use in close support included infantry walking alongside the vehicles to counter enemy infantry tactics.
However, by mid-1944, their speed was not sufficient anymore, nor the firepower. The 90 mm (3.54 in) armed M36 Jackson began to supplement tank hunter units, as well as the M18 Hellcat, which was designed on a lightweight chassis with brand new suspensions and drivetrain, procuring speeds unheard of for a tank in the US military -at least since the famous 1930 Christie.
Both models made their presence well felt throughout 1944, but the M10s were kept in service well into 1945, although after Normandy their gun proved to be unable to harm the Tiger or Panther, until new HVAP rounds were more largely provided. The British Achilles 17 pdr conversion was, in this way, quite successful. Two-tanks batteries of these were often seconded to British tank brigades equipped with Churchill tanks.
The crews also began to protect their tanks by any means, including everything they could carry fastened outside in canvas bags, supplementary racks, and then piling sandbags on the front slope and bulks of timber on the sides. This was particularly apparent by the end of 1944 and the battle of the Bulge, when the German Panzerschreck and Panzerfaust teams began to take a toll. Already in Normandy, the threat of bocage ambushes urged the crews to improvise armored rooftops with panels cut out from enemy tanks. There was an anecdote about an 86th Anti-Tank Regiment (XII Corps) British tank which had its turret crew killed and replaced three times, but the driver and tank itself remained safe.
Another flaw noted in close quarter combat was the slow turning rate of the turret, which was hand-cranked. It needed a staggering two minutes to rotate a full 360 degrees. The tank hunter was conceived for open spaces, to maneuver faster than the enemy tanks, and like a SPG, the tank itself was brought to bear at the same time as the turret was turned. It was still better than most German tank hunters, which were pure SPGs with limited traverse. The Browning cal.50 (12.7 mm) also proved a solution to “clean-up” the surroundings in close quarters. In general, the statistics showed that the M10 spent far more HE rounds than AP ones, indicating they were more usually used in tank roles, rather than as pure tank hunters.
By the end of 1944, some M10s were transferred to the Pacific theater. Their firepower was more than adequate against any IJN tanks, but they proved disadvantaged in wooded areas due to their open-top turret, because of the Japanese practice to have hidden snipers in top trees, and close combat suicidal antitank Japanese infantry tactics.

US Ordnance movie about the M10 GMC


I do not own the rights nor soundtrack of this video, which is displayed solely for educational purposes.

Links about the M10 tank hunter

The M10 “Wolverine” on Wikipedia

M10 GMC specifications

Dimensions (L-W-H) 6.02 x 3.04 x 2.7 m
(19’9″ x 9’11” x 8’10”)
Total weight, battle ready 29.6 metric tons (65,000 lbs)
Crew 4 (driver, commander, gunner, loader)
Propulsion General Motors 6046 diesel, 375 hp (276 kW), 12.5 hp/t
Suspensions VVSS (Vertical Volute Spring Suspensions)
Top speed (flat) 32 mph (51 kph)
Range 186 mi (300 km)
Armament 3″ (76.2 mm) Gun M7, 54 rounds
Cal.50 (12.7 mm) Browning M2HB, 300 rounds
Armor From 0.3 to 2.3 in (9 to 57.2 mm)

Early M10, as delivered in late 1942, training in the USA.
Early M10, as delivered in late 1942, training in the USA.

M10 3in GMC from the 776th Tank Destroyer Battalion, Tunisia, March 1943.
M10 3in GMC from the 776th Tank Destroyer Battalion, Tunisia, March 1943.M10 GMC, Tunisia, April 1943. Notice the counterweight and improvised camouflage, made of sand glued with a brush.
M10 GMC, Tunisia, April 1943. Notice the counterweight and improvised camouflage, made of sand glued with a brush.
M10 GMC from the 636th Tank Destroyer Battalion, Salerno, September 1943.
M10 GMC from the 636th Tank Destroyer Battalion, Salerno, September 1943.
M10 Blitz Buggy from the 654th Tank Destroyer Battalion in Italy, October 1943.
M10 “Blitz Buggy” from the 654th Tank Destroyer Battalion in Italy, October 1943.
M10
3 inch Self Propelled Gun M10, unknown British artillery unit, Italy, mid-1944.
M10 GMC in Sicily, fall 1944.
M10 GMC in Sicily, fall 1944.
M10A1 Wolverine, Normandy, summer 1944.
M10A1 “Wolverine”, Normandy, summer 1944.
M10A1, winter 1944 - Inspiration: E. Boldyrev
M10A1, winter 1944 – Inspiration: E. Boldyrev, battlefield.ru .
M10A1, winter 1944 - Inspiration: E. Boldyrev
Free French Forces M10 “Wolverine” Sirocco, 2nd DB, taking part in the liberation of Paris, August 1944.
Soviet M10 GMC, Northern Front, summer 1944.
Soviet M10 GMC, Northern Front, summer 1944.
M10A1, late production version, unknown unit, France, summer 1944. Notice the extra armored panels on top.
M10A1, late production version, unknown unit, France, summer 1944. Notice the extra armored panels on top.
British 17pdr SP Achilles Ic, Italy, 1944.
British 17pdr SP Achilles Ic, Italy, 1944.

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