Editing Tank destroyer (section)

== World War II ==
Dedicated anti-tank vehicles made their first major appearance in the Second World War as combatants developed effective armoured vehicles and tactics. Some were little more than stopgap solutions, mounting an [[anti-tank gun]] on a tracked vehicle to give mobility, while others were more sophisticated designs. An example of the development of tank destroyer technology throughout the war is the [[Marder III]] and [[Hetzer|Jagdpanzer 38]] vehicles, which were very different in spite of being based on the same chassis: Marder was straightforwardly an anti-tank gun on tracks, whereas the Jagdpanzer 38 traded some firepower (its [[7.5 cm PaK 39|7.5 cm Pak 39]], designed to operate within the confines of a fully armoured fighting compartment, fires the same projectiles from a reduced propellant charge compared to Marder's [[7.5 cm Pak 40]]) for better armour protection and ease of concealment on the battlefield.

Except for most American designs, all tank destroyers were turretless vehicles with fixed or [[casemate]] superstructures. When a tank destroyer was used against enemy tanks from a defensive position such as by ambush, the lack of a rotating [[Gun turret#Combat vehicles|turret]] was not particularly critical, while the lower silhouette was highly desirable. The turretless design allowed accommodation of a more powerful gun, typically a dedicated anti-tank gun (in lieu of a regular tank's general-purpose [[tank gun|main gun]] that fired both anti-tank and high explosive ammunition) that had a longer barrel than could be mounted in a turreted tank on the same chassis. The lack of a turret increased the vehicle's internal volume, allowing for increased ammunition stowage and crew comfort.{{sfn|Perrett| 1987 |p=84}} Eliminating the turret let the vehicle carry thicker armour, and also let this armour be concentrated in the hull. Sometimes there was no armoured roof (only a weather cover) to keep the overall weight down to the limit that the chassis could bear. The absence of a turret meant that tank destroyers could be manufactured significantly cheaper, faster, and more easily than the tanks on which they were based, and they found particular favor when production resources were lacking.

=== Germany ===
[[File:Bundesarchiv Bild 101I-782-0041-31, Nordafrika, Panzerjäger 1.jpg|thumb|''[[Panzerjäger I]]'']]

The first [[Nazi Germany|German]] tank destroyers were the ''[[Panzerjäger]]'' ("Tank Hunters"), which mounted an existing anti-tank gun on a convenient chassis for mobility, usually with just a three-sided [[gun shield]] for crew protection. For instance, 202 obsolete [[Panzer I]] light tanks were modified by removing the turret and were rebuilt as the [[Panzerjäger I]] self-propelled [[4,7cm KPÚV vz. 38|4.7 cm PaK(t)]]. Similarly, [[Panzer II]] tanks were used on the eastern front. Captured Soviet {{nowrap|76.2 mm}} anti-tank guns were mounted on modified Panzer II chassis, producing the [[Marder II]] self-propelled anti-tank gun. The most common mounting was a German {{nowrap|75 mm}} anti-tank gun on the Czech [[Panzer 38(t)]] chassis as the [[Marder III]]. The Panzer 38(t) chassis was also used to make the [[Hetzer|Jagdpanzer 38]] casemate style tank destroyer. The Panzerjäger series continued up to the {{nowrap|88 mm}} equipped [[Nashorn]].

German tank destroyers based on the [[Panzer III]] medium tank and later German tanks had more armour than their tank counterparts. One of the more successful German tank destroyers was designed as a self-propelled artillery gun, the ''[[Sturmgeschütz III]]''. Based on the Panzer III tank chassis, the ''Sturmgeschütz III'' was originally fitted with a short barreled low-velocity howitzer-like gun, and was assigned to the artillery arm for infantry fire support as an [[assault gun]]. Later, after encountering Soviet tanks, it was refitted with a comparatively short-barreled high-velocity anti-tank gun, usually with a [[muzzle brake]], enabling it to function as a tank destroyer. The ''Sturmgeschütz III'' from its 1938 origin used a new casemate-style superstructure with an integrated design, similar to the later ''[[Jagdpanzer]]'' vehicle designs' superstructure, to completely enclose the crew. It was employed in infantry support and offensive armoured operations as well as in the defensive anti-tank role. The StuG III assault gun was Germany's most-produced fully tracked armoured fighting vehicle during World War II, and second-most produced German armoured combat vehicle of any type after the [[Sd.Kfz. 251]] [[half-track]].

[[File:Jagdpanther2.jpg|thumb|right|''[[Jagdpanther]]'']]

Although the early German ''Panzerjäger'' carried more effective weapons than the tanks on which they were based, they were generally lacking in protection for the crew, having thinly armoured open-topped superstructures. The "open-topped" design format of the ''Panzerjäger'' vehicles was succeeded by the ''[[Jagdpanzer]]'' ("hunting tanks"), which mounted the gun in true casemate-style superstructures, completely enclosing the crew compartment in armor that was usually integral to the hull. The first of these ''Jagdpanzer''s was the 70-ton ''Ferdinand'' (later renamed ''[[Elefant]]''), based on the chassis, hulls, and drive systems of ninety-one Porsche [[VK 4501 (P)|VK4501 (P)]] heavy tanks,{{Efn|The hulls had been built by Porsche in expectation of selection as a heavy tank but had been rejected in favour of what became the [[Tiger I]].}} mounting a long-barreled [[8.8 cm Pak 43|88 mm]] cannon in an added casemate, more like the earlier ''Panzerjägers'' had with their added-on armour shielding for the gun crew, but in the ''Ferdinand'' completely enclosing the gun and firing crew in the added casemate, as the later purpose-built ''Jagdpanzers'' would. However, the ''Ferdinand'' was mechanically unreliable and difficult to maneuver, and once all ninety-one unturreted "Porsche Tiger" hulls/drive systems were converted, no more were built. The German Army had more success with the [[Jagdpanther]]. Introduced in mid-1944, the Jagdpanther, of which some 415 examples were produced, was considered the best of the casemate-design Jagdpanzer designs.<ref name="tanks">Forty and Livesey 2006 p. 33</ref> It featured the same powerful PaK 43 88 mm cannon used on the unwieldy ''Elefant'', now fitted to the chassis of the medium [[Panther tank]], providing greatly improved armour-penetrating capability in a medium-weight vehicle.

Facing an increasingly defensive war, the German Army turned to larger and more powerfully armed Jagdpanzer designs, and in July 1944 the first ''[[Jagdtiger]]'' rolled off the production line; it was the heaviest German armoured fighting vehicle to go into active service.<ref name="tanks"/>  The ''Jagdtiger'' was based on the [[Tiger II]] heavy tank featured a very large [[12.8 cm Pak 44|128 mm PaK 44]] cannon and heavy armour protection. Only 88 ''Jagdtiger'' vehicles were produced, barely matching the total number of the earlier Ferdinand / Elefant vehicles. They were first deployed to combat units in September 1944.

[[File:Jagdtiger 1 Bovington.jpg|thumb|''[[Jagdtiger]]'']]

The decision of German armoured vehicle designers to use a casemate-style superstructure for all tank destroyers had the advantage of a reduced silhouette, allowing the crew to more frequently fire from defilade ambush positions. Such designs were also easier and faster to manufacture and offered good crew protection from artillery fire and shell splinters. However, the lack of a rotating turret limited the gun's traverse to a few degrees. This meant that the driver normally had to turn the entire tank onto its target, a much slower process than simply rotating a powered turret.<ref>Irwin, John P. ''Another River, Another Town'', New York: Random House Publishers (2002), pp. 61–61</ref> If the vehicle became immobilized due to engine failure or track damage, it could not rotate its gun to counter opposing tanks, making it highly vulnerable to counterfire.<ref>Irwin, pp. 61–61</ref> This vulnerability was later exploited by opposing tank forces. Even the largest and most powerful of German tank destroyers were found abandoned on the field after a battle, having been immobilized by one or more hits by high explosive (HE) or armour-piercing (AP) shells to the track or front drive sprocket.<ref>Irwin, pp. 61–62: Even the U.S. M4 Sherman could disable a Jagdpanther's track or fracture the front drive sprocket with a 75&nbsp;mm HE shell. As the crew abandoned their vehicle, they were easy targets for enemy machinegun fire.</ref>

=== Italy ===
{{Refimprove section|date=January 2024}}
[[File:Semovente M42.Saumur.0008fefh.jpg|thumb|[[Semovente da 75/18]]]]

The most famous Italian tank destroyer of the Second World War was a self-propelled gun. The [[Semovente da 75/18]], based on the [[M13/40 tank|M13/40]] frame, was developed to support front-line infantry, and therefore had fixed armament: a 75 mm gun in casemate. However, thanks to its low height (185 cm) and the caliber of its gun the 75/18 also had good results in anti-tank combat, fighting against British and American (but not Soviet) units. After the [[Armistice of Cassibile|Armistice of 1943]], the 75/18 remained in use by German forces.

Built on the same frame, the [[Semovente da 105/25]] was equipped with a 105 mm gun and known as "''bassotto''" (Italian for [[dachshund]]) due to its lower height.<ref>{{cite web |last1=Giusti |first1=Arturo |last2=Pantelic |first2=Marko |title=Semovente M43 da 105/25 |url=https://tanks-encyclopedia.com/semovente-105-25/ |website=The Tank Encyclopedia |access-date=24 January 2024 |date=28 July 2021}}</ref> As manufacturing began in 1943, the 105/25 was used by German forces. A further development was the [[Semovente da 75/46]], which had a longer gun than the 75/18 and inclined armour 100 mm thick, making it similar to [[Sturmgeschütz III|''Sturmgeschütz'' III]]. Only 11 of these were manufactured. Before the Semovente da 75/18, the [[Semovente da 47/32|L40]], built on an [[L6/40 tank|L6/40]] light tank chassis, saw action in Africa and in Russia, but with disappointing results.

=== Japan ===
[[File:Type 3 Ho-Ni III.jpg|thumb|[[Type 3 Ho-Ni III]]]]

The [[Type 1 Ho-Ni I]] was the first self-propelled gun design of the [[Imperial Japanese Army]].{{sfn|Tomczyk|2007|p=15}} They were meant to be [[self-propelled artillery]] and tank destroyers for [[Division (military)|armoured divisions]].{{sfn|Tomczyk|2007|p=3}}{{sfn|Zaloga|2012|p=34}} The plan was for the Type 1 Ho-Ni I gun tank to form part of a fire support company in each of the tank regiments.{{sfn|Zaloga|2012|p=34}} The Type 1 Ho-Ni I was developed by using the existing [[Type 97 Chi-Ha medium tank]] chassis and engine, and replacing the [[gun turret]] with a [[Type 90 75 mm field gun]] mounted in an open [[casemate]] with frontal and side armour only.{{sfn|Zaloga|2007|p=19}} They entered service in 1942 and were first deployed in combat at the [[Battle of Luzon]] in the [[Philippines]] in 1945. Some were used in static entrenched positions.{{sfn|Zaloga|2007|pp=37–39}}

A variant, known as the Type 1 Ho-Ni II mounted a [[Type 91 10 cm howitzer|Type 91 105 mm howitzer]] and had a slightly changed superstructure as far as the side armor with re-positioned observation visors.{{sfn|Tomczyk|2007|pp=10, 20}} Production began in 1943, with only 54 completed.{{sfn|Zaloga|2007|p=19}}

The other variant produced was the [[Type 3 Ho-Ni III]], which mounted a [[Type 3 75 mm tank gun]] in a completely enclosed armored casemate to address the issue of crew protection in close combat.{{sfn|Zaloga|2007|pp=19, 21}}{{sfn|Tomczyk|2007|pp=9, 27}} The welded superstructure had sloped armour and the gun mount had additional stamped armour plate.{{sfn|Tomczyk|2007|pp=7–8}} The total number produced of all three types in the Ho-Ni series were 111 units.{{sfn|Zaloga|2007|p=19}} Most of the Ho-Ni units were retained within the [[Japanese home islands]] to form part of the defenses against the projected [[Operation Downfall|American invasion]], and did not see combat before the [[surrender of Japan]].{{sfn|Zaloga|2007|p=20}}{{sfn|Tomczyk|2007|p=8}}

The [[Type 2 Ho-I]] Gun tank used the [[Type 1 Chi-He medium tank]] chassis.{{sfn|Zaloga|2007|p=21}} It was designed as a [[self-propelled howitzer]], mounting a short barreled Type 99 75 mm gun to provide close-in fire support.{{sfn|Zaloga|2007|p=21}}<ref>{{cite web| url = http://www.historyofwar.org/articles/weapons_type_2_ho_i.html| title = History of War: Type 2 Ho-I Gun Tank}}</ref> For deployment, the gun tank was intended to be used in a fire support company for each of the tank regiments. No Type 2 Ho-I gun tanks are known to have engaged in combat prior to Japan's surrender. The prototype was built in 1942 and 31 units were produced in 1944.{{sfn|Zaloga|2007|p=21}}

The [[Type 4 Ho-Ro]] self-propelled artillery used a modified Type 97 chassis. On to this platform, a [[Type 38 15 cm howitzer|Type 38 150 mm howitzer]] was mounted.{{sfn|Zaloga|2007|p=20}} The main gun could fire Type 88 APHE rounds and [[HEAT]] rounds. Given its breech loader, the maximum rate of fire was only 5 rounds per minute.{{sfn|Tomczyk|2007|p=9}} The gun's elevation was restricted to 30 degrees by the construction of the chassis. Other design issues included the fact that although the gun crew was protected by a [[gun shield]] with armour thickness of 25 mm at the front, the shield only extended a very short distance on the sides;{{sfn|Tomczyk|2007|pp=11, 13, 23–26}} leaving the rest of the sides and back exposed. They were rushed into service, deployed and saw combat during the [[Philippines Campaign (1944–45)|Philippines Campaign]] in the last year of [[World War II]].{{sfn|Zaloga|2007|pp=38, 39}} Remaining units were deployed to [[Okinawa Prefecture|Okinawa]] in ones and twos for island defense during the [[Battle of Okinawa]], but were severely outnumbered by American artillery.{{sfn|Trewhitt|1999|p=108}}

=== Soviet Union ===
[[File:SU-100 in the Military-Historical Museum of Artillery, Engineering Troops and Signal Corps. St. Petersburg.jpg|thumb|Soviet [[SU-100]] in the [[Military Historical Museum of Artillery, Engineers and Signal Corps]]]]
{{Main|Samokhodnaya Ustanovka}}

As with the Germans of 1943, most of the [[Soviet Union|Soviet]] designs mounted anti-tank guns, with limited traverse in casemate-style turretless hulls, in a general design format looking much like the Germans' own ''Jagdpanzer'' vehicles. The results were smaller, lighter, and simpler to build weapons that could carry larger guns than any contemporary tank, including the King Tiger. The Soviets produced high numbers of the {{nowrap|85 mm}} [[SU-85]] and {{nowrap|100 mm}} [[SU-100]] self-propelled guns based on the same chassis as the [[T-34]] medium tank; the heavier-duty powertrain and hull of the [[IS-2]] heavy tank were instead used to produce the heavier-hitting {{nowrap|122 mm}}-armed [[ISU-122]] and {{nowrap|152 mm}}-armed [[ISU-152]], both of which had impressive anti-tank capabilities earning each of them the Russian nickname ''Zveroboy'' ("beast killer") for their ability to destroy German [[Tiger I tank|Tigers]], [[Panther tank|Panthers]] and [[Elefant]]s. The predecessor of the ISU 152 was the [[SU-152]], built on the KV-1s chassis and shared many similarities (including its gun) with the ISU-152. The ISU-152 built as a heavy assault gun, relied on the weight of the shell fired from its M-1937/43 howitzer to defeat tanks.<ref name="tanks2">Forty and Livesey 2006 p. 329</ref> In 1943, the Soviets also shifted all production of light tanks like the [[T-70]] to much simpler and better-armed [[SU-76]] self-propelled guns, which used the same drive train. The SU-76 was originally designed as an anti-tank vehicle, but was soon relegated to the infantry-support role.<ref name="tanks3">Forty and Livesey 2006 p. 392</ref>

=== United States ===
{{Main|Tank destroyer battalion (United States)|List of tank destroyer units of the United States Army}}
{{Redirect|Gun motor carriage||Self-propelled artillery}}

[[United States Army|U.S. Army]] and counterpart British designs were very different in conception. U.S. doctrine was based, in light of the [[fall of France]], on the perceived need to defeat German [[blitzkrieg]] tactics, and U.S. units expected to face large numbers of German tanks, attacking on relatively narrow fronts. These were expected to break through a thin screen of anti-tank guns, hence the decision that the main anti-tank units—the [[Tank destroyer battalion (United States)|Tank Destroyer (TD) battalions]]—should be concentrated and very mobile. In practice, such German attacks rarely happened. Throughout the war, only one battalion ever fought in an engagement like that originally envisaged (the [[601st Tank Destroyer Battalion|601st]], at the [[Battle of El Guettar]]). The Tank Destroyer Command eventually numbered over 100,000 men and 80 battalions each equipped with 36 self-propelled tank destroyers or towed guns.

[[File:75 mm M3 GMC (cropped).jpg|thumb|The first US tank destroyer was a 75 mm gun on a half-track chassis]]
[[File:Aberdean proving grounds 036.JPG|right|thumb|[[M10 tank destroyer]]]]

Only [[Shoot-and-scoot|a few shots were expected to be fired from any firing position]]. Strong reconnaissance elements were provided so that TDs could use pre-arranged firing positions to best advantage. [[Flanking fire]] by TDs was emphasized, both to penetrate thinner enemy side armour, and to reduce the likelihood of accurate enemy return fire.

All American tank destroyers were officially known by exactly the same collective term used for American self-propelled artillery ordnance, "gun motor carriage". The designs were intended to be very mobile and heavily armed. Most of the tank-hull based designs used special open-topped turrets of a differing design from the original tank it was based on, which was meant to both save weight and to accommodate a larger gun. The earliest expedient design was mounting a [[75 mm M1897 field gun]] in a limited-traverse mount on an [[M3 half-track]], which was designated  [[M3 GMC|75 mm gun motor carriage M3]]. Another, considerably less successful, early design was the [[M6 gun motor carriage]] which mounted the US 37 mm anti-tank gun facing to the rear on the bed of a Dodge 3/4-ton light truck. 

The M3 was first used against the Japanese in the Philippines and then in the Tunisian campaign of the war in North Africa. Some were supplied to British units who used them within [[Armoured car regiment|armoured car reconnaissance regiments]] for fire support.  The M6 GMC was unarmoured and the 37 mm gun was ineffective against most enemy tanks by the time it entered service.

By far the most common US design, and the first that was fully tracked and turreted (which became the American hallmark of World War II "tank destroyer" design) was the [[M10 tank destroyer|3-inch gun motor carriage M10]], later supplemented by the [[M36 tank destroyer|90 mm gun motor carriage M36]]—both based on the [[M4 Sherman]] hull and powertrain—and the [[M18 Hellcat|76 mm gun motor carriage M18 (Hellcat)]], based on a unique hull and powertrain design, with a slight visual resemblance to what was used for the later [[M24 Chaffee]] light tank. The M18 came closest to the US ideal; the vehicle was very fast, small, and mounted a {{nowrap|76 mm}} gun in a roofless open turret. The M36 Jackson GMC possessed the only American-origin operational gun that could rival the German [[8.8 cm Pak 43]] anti-tank gun and its tank mounted variant, the [[90 mm gun M1/M2/M3|90 mm M3 gun]], and the M36 remained in service well after World War II. The only dedicated American casemate hull design fighting vehicle of any type built during the war, that resembled the German and Soviet tank destroyers in hull and general gun mounting design, was the experimental [[T28 super-heavy tank]], which mounted a 105 mm T5E1 long-barrel cannon. This gun had a maximum firing range of 12 miles (20 km), and the vehicle was originally designed as a very heavily armoured self-propelled assault gun to breach Germany's [[Siegfried Line]] defenses.

Of these tank destroyers, only the {{nowrap|90 mm}} gun of the M36 proved effective against the frontal armour of Germans' larger armored vehicles at long range.<ref>Forty and Livesey 2006 p. 117</ref> The open top and light armour made these tank destroyers vulnerable to anything greater than small-arms fire. As the number of German tanks encountered by American forces steadily decreased throughout the war, most battalions were split up and assigned to infantry units as supporting arms, fighting as [[assault gun]]s or being used essentially as tanks. In this sense they were an alternative to the [[Independent tank battalion]]s that were attached to various Infantry Divisions.

The expectation that German tanks would be engaged in mass formation was a failed assumption. In reality, German attacks effectively used [[combined arms]] on the ground, fighting cohesively. American tank destroyer battalions comprised three tank destroyer companies supported by nine security sections. The single-purpose tactics of the tank destroyer battalion failed to account for non-tank threats.<ref name="single purpose">{{cite book|last1=Gabel|first1=Christopher R.|title=Seek, Strike and Destroy: US Army Tank Destroyer Doctrine in World War II|publisher=DIANE Publishing|isbn=9781428915770|pages=68–69|url=https://books.google.com/books?id=IA1ljqnb7IwC&q=main+battle+tank+doctrine&pg=PA70|access-date=4 May 2015|year=1985}}</ref>

In the 1950s the goal of providing airborne forces with a parachute-capable self-propelled anti-tank weapon led to the deployment of the [[M56 Scorpion]] and [[M50 Ontos]]. The concept later led to the [[M551 Sheridan]] light tank of the mid-1960s.

=== United Kingdom ===
[[File:Achilles tank destroyer on the east bank of the Rhine.jpg|thumb|A British Achilles self-propelled anti-tank gun on the east bank of the [[Rhine]] following [[Operation Plunder]]]]
British tanks in the early years of the war, both [[infantry tank]]s and [[cruiser tank]]s, were (with the exception of the pre-war [[Matilda I (tank)|Matilda I]] design) equipped with a gun capable of use against contemporary enemy tanks—the 40&nbsp;mm [[Ordnance QF 2 pounder]]. This was replaced with the 57 mm [[Ordnance QF 6 pounder]] when that became available. There was extra impetus given to the development of anti-tank weaponry, which culminated in the 76mm [[Ordnance QF 17 pounder]], widely considered one of the best anti-tank guns of the war.<ref name="tanks4">Forty and Livesey 2006 p. 116</ref>

Towed anti-tank guns were the domain of the [[Royal Artillery]] and vehicles adapted to mount artillery, including anti-tank self-propelled guns such as the [[Deacon (artillery)|Deacon]] (6pdr on an armoured wheeled truck chassis) and [[Archer (tank destroyer)|Archer]] (17pdr on tracked chassis) and US-supplied vehicles, were their preserve rather than the [[Royal Armoured Corps]].

The self-propelled guns that were built in the "tank destroyer" mould came about through the desire to field the QF 17 pounder anti-tank gun and simultaneous lack of suitable standard tanks to carry it. As a result, they were of a somewhat extemporized nature. Mounting the gun on the [[Valentine tank]] chassis in a fixed superstructure gave the [[Archer (tank destroyer)|Archer]], looking somewhat like the light-chassis German [[Marder III]] in appearance. The 17 pounder was also used to re-equip the US-supplied [[M10 tank destroyer]], replacing the American 3-inch gun to produce the [[17pdr SP Achilles]].

In 1942 the General Staff agreed on investigating self-propelled mountings of the 6-pounder, 17-pounder, [[QF 3-inch 20 cwt|3-inch 20cwt]] guns and the 25-pounder field gun/howitzer on the [[Matilda II]], [[Valentine tank|Valentine]], [[Crusader tank|Crusader]] and [[Cavalier tank|Cavalier (Cruiser Mark VII)]] tank chassis. In October 1942 it was decided to progress using the Valentine chassis with a 17-pdr (which would become Archer) and 25-pdr (which entered service as [[Bishop (artillery)|Bishop]]).<ref>{{cite web| url = http://www.tankmuseum.org/museum-online/vehicles/object-e1969-43| title = S-P 17pdr, Archer (E1969.43)}}</ref>

While there was a general move to a general purpose gun that was usable against both tanks and in supporting infantry, there was a need to put the 17 pdr into a tank for use against the enemy's heavy tanks. The [[Cruiser Mk VIII Challenger]] was a project to bring a 17 pdr tank into use to support the [[Cromwell tank|Cromwell cruiser tank]]. Delays led to it being outnumbered in use by the [[Sherman Firefly]]—but a derivative of Challenger was the more or less open-topped variant ''Avenger'', which was delayed until post war before entering service. A cut-down 17 pdr, the 77mmHV was used to equip the [[Comet tank]] in the last year of the war.
[[File:Archer SP 17 pdr Tank Destroyer.jpg|thumb|Self-propelled 17pdr, Valentine, Mk I, Archer. The gun faced to the rear.]]

The closest the British came to developing an armoured tank destroyer in the vein of the German Jagdpanzers or Soviet ISU series was the Churchill 3-inch gun carrier—a [[Churchill tank]] chassis with a boxy superstructure in place of the turret and mounting a [[QF 3-inch 20 cwt|3-inch anti-aircraft gun]]. Although a number were ordered and fifty delivered in 1942,<ref>Chamberlain & Ellis, 1969. p68-69</ref> they were not put into service as the immediate threat passed. The design was rejected in favor of developing a 17 pounder armed Cromwell tank variant, ultimately leading to the [[Comet tank]]. The [[Tortoise (tank)|Tortoise]] "heavy assault tank", intended for use in breaking through fixed defensive lines, was well armoured and had a very powerful 32-pounder (94&nbsp;mm) gun, but did not reach service use.

By 1944, a number of the [[Sherman tank|Shermans]] in British use were being converted to [[Sherman Fireflies]] by adding the QF 17 pounder gun. Initially this gave each [[troop]] (platoon) of Shermans one powerfully armed tank. By war's end—through the production of more Fireflies and the replacement of Shermans by British tanks—about 50% of Shermans in British service were Fireflies. The Sherman Firefly, however, is not considered a tank destroyer since it could still perform the other duties of the regular [[M4 Sherman]], albeit the Firefly was less capable due to the late development of a HE round for the QF 17 pounder.

=== Romania ===
[[File:Mareșal tank destroyer M-05 prototype.jpg|thumb|The Romanian [[Mareșal tank destroyer]], developed starting in late 1942, is proposed to have inspired the German [[Hetzer]]'s design.]]

Until 1942, the Romanian tank force was equipped exclusively with obsolete [[R-1 tank|R-1]], [[Panzer 35(t)#Variants|R-2]] and [[Renault R35#Romania|R35]] tanks. Having faced big problems against Soviet T-34 and KV-1 tanks on the Eastern Front, the Romanian Army leadership sought for ways to improve its anti-tank capabilities. The initial plan was the creation of [[1942 medium tank (Romania)|a tank comparable in characteristics to the T-34]];{{sfn| Axworthy |Scafeș |Crăciunoiu|1995 |p=221 }} instead, Romania went for a number of tank destroyers, since they were more adequate for its industry.

The [[Mareșal tank destroyer|Mareșal]] is probably the best known Romanian AFV from the war; historians [[Steven Zaloga]] and Mark Axworthy state that it inspired the design of the later German [[Hetzer]].{{sfn| Axworthy |Scafeș |Crăciunoiu|1995 |p=233 }}<ref>{{cite book |last1=Zaloga |first1=Steven J. |title=Tanks of Hitler's Eastern Allies 1941-45 |date=2013 |page=31| publisher=Osprey Publishing |location=Oxford, UK |isbn=978-1-78096-020-3}}</ref> Standing at only around 1.5 m tall, which would have made it very difficult to hit for its enemies, the Mareșal was a lightly armored, but highly mobile vehicle. It was armed with the Romanian [[75 mm Reșița Model 1943|75 mm Reșița M1943]] anti-tank gun, which proved to be among the best of its class during World War II, according to Mark Axworthy. During tests, the Mareșal proved to be superior in many aspects to the [[Sturmgeschütz III|StuG III G]], against which it competed. Those facts suggest that the Mareșal would have been an effective tank destroyer, had it been deployed into combat. There were, however, also critics of the vehicle, especially among high-ranking Romanian officials. It never saw action because the invading Soviet army had stopped its production.{{sfn| Axworthy |Scafeș |Crăciunoiu|1995  |p=228-235, 237}}

Other Romanian tank destroyers include the [[TACAM R-2]] and [[TACAM T-60]], which were converted from [[Panzer 35(t)#Variants|R-2]] and [[T-60]] light tanks respectively. Both of them saw action. One TACAM R-2 survives today and is displayed at the [[National Military Museum, Romania|National Military Museum]] in [[Bucharest]].{{sfn| Axworthy |Scafeș |Crăciunoiu|1995 |p=221-225 }} Another conversion was the [[Renault R35#Romania|VDC R-35]], Romania's only turreted tank destroyer. Two other proposed tank destroyers existed: the [[TACAM R-1]] and [[TACAM T-38]].{{sfn| Axworthy |Scafeș |Crăciunoiu|1995 |p=225-228 }}

=== Poland ===
Variants of the Polish [[TKS]] and [[TKS|TK-3]] tankettes up-armed with 20&nbsp;mm gun (23–26 vehicles) were operationally deployed in the [[invasion of Poland]].<ref>A. Jońca, R. Szubański, J. Tarczyński, Wrzesień 1939 Pojazdy Wojska Polskiego, Wyd. WKiŁ, Warszawa 1990, s. 72.</ref> They were used as an anti-tank component of the reconnaissance units. There were also 37&nbsp;mm armed [[TKS-D]] (2 experimental vehicles) and 47&nbsp;mm armed [[TKS|TKD]] (4 experimental vehicles). It is not certain whether they were used operationally at all.

=== France ===
Due to the quick defeat of France, few French vehicles were built.  The Laffly W15 TCC (''Chasseur de chars'') was an attempt to quickly build a light tank destroyer by mounting a 47&nbsp;mm SA37 anti-tank gun onto a lightly armoured [[Laffly S15|Laffly W15T]] artillery tractor. Other French tank destroyers were being developed, including the SOMUA SAu-40, ARL V39 and various ad hoc conversions of the [[Lorraine 37L]].{{Citation needed|date=September 2020}}