M36 Gun Motor Carriage (Jackson / Slugger) Tank Destroyer / Gun Motor Carriage
The M36 Jackson / Slugger was basically an enhanced version of the outmoded M10 tank destroyer.
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The United States Army was fielding the capable M10 series as its standard tank destroyer of World War 2. It was produced from 1942 into 1943 to the tune of some 6,700 examples and also saw use with Allied nations. It was developed upon the chassis of the M4A3 Sherman medium tank series which made them large, heavy targets but logistically-friendly. Primary armament was an adequate 76.2mm main gun. While capable of tackling the medium-class German tanks of the war, the situation changed with the arrival of the Panther and Tiger I series of heavy tanks - both featuring much improved frontal armor protection and heavy caliber main guns. The days of the M10, it seemed, were numbered for its base main gun system was proving ever-more inadequate against the new generation of enemy tanks.
As soon as the M10 entered serial production, the US Ordnance Department began looking into up-gunning the M10 series and trialled a 90mm M3 high-velocity anti-tank gun mounting with the M10A1 design (made from the Sherman M4A2 hull). However, the M10 turret, as it stood, was not intended for such a gun so a new turret design was initiated. It its modified form, the vehicle came under the prototype designation of "T71 GMC" (GMC = "Gun Motor Carriage"). In June of 1944, the T71 was officially designated as the "M36 GMC" which began deliveries to the European battlefronts by the end of the year. Another variant based on the Sherman M4A3 hull and mounting the 90mm gun were converted for the tank destroyer role to become 187 examples of the "M36B1". The similar "M36B2" provided the 90mm gun turret atop the M4A2 chassis and M10 hull with power from a diesel engine. 287 of this type were converted as such. Like other armored American vehicles lacking any sort of imaginative name, the British stepped in to nickname the M36 the "Jackson" after famed American Civil War General "Stonewall Jackson" (consistent with the M5 General Stuart, M3 General Lee/Grant and M4 General Sherman). To others, it was simply known as the "Slugger". Approximately 1,772 M36 examples of all types were eventually completed - either as new-build or as conversion models. Of these, 1,298 were made up of the original base M36 models (M10A1 hull / M4A3 chassis).
The M36 formally replaced the M10 series in the US Army inventory. As in the M10 before it, the M36 was completed with an open-topped turret to save on weight. This also allowed much needed head room for the gunnery crew in the turret while supplying the tank commander with unobstructed views of the action ahead. However, this also opened the crew to the dangers of warfare as well as the elements . An optional folding armor roof kit was issued to provide some level of point protection for the turret crew.
Primary armament centered around the 90mm M3 series main gun. The American 76.2mm was always considered a step below the British gun of same caliber and even the German 75mm. The British Army even changed the 76.2mm main guns of their arriving Lend-Lease American M10s to British 76.2mm anti-tank types. As such, the 90mm caliber was a necessity for the newer American design in an effort to penetrate the front stout armor of German Panthers and Tiger Is and, upon inception of the M36 into service, the Allies finally had a weapon system capable of engaging these powerful enemy tanks. Of course the usual flanking maneuver was still in order - attacking the sides and rear of these German beasts to help achieve uncontested direct hits to the more vulnerable sides - this even before the slow-reacting turrets of the Panthers and Tiger Is could counter the threat. High velocity armor-piercing ammunition appearing later in the war only served to improve the inherent penetrative powers of the M3 gun. 47 projectiles of 90mm ammunition were stowed within the vehicle, most of these within easy reach. The large structural overhang at the rear of the turret worked to stow some of these projectiles while also doubling as a counterweight of sorts for the 90mm gun.
Self-defense was solved by the installation of a trainable 12.7mm Browning M2HB heavy machine gun. This weapon system fired large caliber, armor-piercing ammunition with a good rate-of-fire and could be suitable against formations of enemy infantry (as suppression or direct attack), light vehicles or low-flying enemy aircraft. 1,000 rounds of 12.7mm ammunition was carried aboard.
The M36 shared a similar external appearance to the M10 before it. The hull was not unlike the Sherman though sporting side superstructure panels that angled inwards towards the hull roof line. "Pioneer" tools could be stowed along the side panels of the vehicle during transport. The glacis plate was well sloped to provide for some basic ballistics protection at the front. The engine was fitted to the rear as was the track idler with the drive sprocket to the front of the vehicle. The track system was decidedly Sherman with its paired road wheel bogies but the turret design was of an all-new approach, more akin to the angled sides of the M10. The turret sported a rounded shape along the sides with a heavy armored gun mantlet at the base of the long-barreled gun system. The gun could also be capped with a double-baffled muzzle brake to counter recoil.
Power for the M36 frame was supplied by a Ford GAA 8-cylidnder gasoline-fueled engine delivering 450 horsepower output (the M36B2 sported a diesel engine). This translated to a top speed of 26 miles per hour with an operational range of 150 miles in ideal conditions. The powerplant was coupled with a synchromesh transmission system allowing five forward and one reverse speed settings. The vehicle was crewed by five personnel made up of the driver, tank commander, gun layer and two ammunition handlers. The turret-mounted 12.7mm defensive machine gun could be manned by any of the turret crew as only the driver sat segregated in a compartment at the front-left of the hull. However, he was the only crew member protected from small arms fire and the elements. The rest of the operating crew resided in the turret.
The vehicle stood at over 10 feet tall which promoted a tempting target to the enemy. She weighed in at nearly 28 tons, making her a heavy and somewhat cumbersome beast for finesse maneuvering through woods or village streets. The chassis was suspended by the typical-Sherman Vertical Volute Spring Suspension (VVSS) system as in the M10 series.
In action, the M36 series acquitted itself rather well for being a hastily generated M4 Sherman conversion offspring. It offered up the necessary firepower for the current battlefield requirement and was available in enough numbers to make a difference in many European engagements. Of course the type was outshined by the arrival of the M18 "Hellcat" tank destroyer models which proved to be light, fast, agile, reliable and adequately armed for the role. Towards the end of the war, use of dedicated tank destroyer battalions ended as such vehicles were now being issued to regular mechanized groups, fighting alongside combat tanks and infantry units. In this role, they could also serve as assault guns and self-propelled artillery while benefitting from aerial cover provided by Allied strike aircraft. The tank destroyer in US Army doctrine, therefore, died with the end of the war in 1945.
Beyond combat actions in World War 2, the M36 went on to see extended service in the upcoming Korean War which proved to be a mish-mash of World War 2-era and Cold War-era weapons for all sides. In the conflict, the M36 fared well against the highly-touted Soviet T-34 medium tanks that so soundly repelled the German invasion in World War 2 along the East Front. Additional combat was seen through foreign parties in the 1st Indochina War, the Indo-Pak War of 1965 and - much later - in the Croatian War of Independence and the Bosnian War of the 1990s - an amazing testament to the M36's design and ultimate global reach.