Tracklink Article - British tank armament in the Second World War 

This was originally published in Issue 109 (Autumn 2021) and Issue 111 (Spring 2022) of  Tracklink, the magazine of the tank Museum.  It had originally been planned to publish the second part in issue 110, but a production issue with the magazine prevented this, creating an unfortunate gap between the two parts.  Both parts are included below

British tank armament in the Second World War - Part 1

It is generally accepted that British tanks were inadequately armed for most of WW2. This initially seems strange, since the construction and tactical use of artillery was among the British Army's greatest strengths during the same period. The first part of this article will look at the 1940 and North Africa campaigns, while the second part will look at how British armour met the new challenges of North-west Europe.

At the start of the war, the most common British tanks (almost 900 of the roughly 1,000 tanks available in September 1939) were the Light Tank Mk VI and the A11 Matilda I, both armed only with machine-guns These had the advantage of cheapness during the depression of the 1930s when most of the limited defence funding went to the navy or RAF, but their light armament limited their effectiveness. Perhaps the only saving grace of the heavy AFV losses during the 1940 campaign was that most of them were these vehicles, which Britain could most afford to lose.

The few tanks with heavier armament almost all mounted the 2 pdr (40mm). This had good AP performance for the time it was introduced, but its small calibre meant its HE round was ineffective as it contained little explosive filler and few HE rounds were produced.

A small number of vehicles (typically two in each squadron HQ) were therefore completed as “Close Support” (CS) tanks, with 3in or 3.7in howitzers, but these were too few and primarily intended to fire smoke rather than HE. British tank units thus had far too little HE capability, which would soon prove a serious problem.

Perhaps inspired by the French Char B1 (which the British briefly considered purchasing), the first Churchill infantry tanks were built with a turreted 2 pdr and a 3in howitzer in the hull. The howitzer was intended to fire smoke rounds and high explosive rounds against infantry positions, against which the small solid 2 pdr AP rounds were ineffective.

However, its placement low in the hull between the protruding track horns limited traverse and elevation, and thus both range and usefulness of the weapon. Worse, it was loaded and aimed by a single crewman working in a very cramped position, reducing rate of fire. As only a few hundred howitzers were available, it was quickly replaced by a second Besa.

It is notable that the Royal Armoured Corps chose to equip both cruiser tanks (intended for a semi-independent “cavalry” role ) and the slower and more heavily armoured infantry support tanks with the same weapon, given their very different roles.

It is particularly interesting that the weapon chosen was one optimised for armour penetration, and of little use for anything else. For the infantry tanks particularly, while one of their roles was to provide anti-tank support to help the infantry hold the ground they had taken, Great War experience should have shown that providing a weapon capable of firing effective HE rounds to deal with enemy MG positions was at least equally important.

It is tempting to see this RAC concentration on armour penetration rather than general utility as a reflection of its own institutional belief that the tank would be the decisive weapon on the modern battlefield, and therefore the priority was to destroy enemy tanks. Sadly, such insular views of the tank as a war winner in itself – unfortunately characteristic of the interwar Tank Corps - proved less effective than the German Blitzkrieg doctrines, which saw the tank as only one component of a more balanced force.

Although the 2 pdr had performed reasonably during the 1940 campaign, Brigadier Vyvyan Pope, the BEF's advisor on armoured warfare, noted that “The two pounder is good enough for now, but only just. We must mount something better” (1).

Indeed, it had been recognised as early as 1938 that a more powerful weapon would be needed to keep pace with developments in enemy armour, and design of a replacement 6 pdr (57mm) weapon had already begun.

Though the new gun had been designed and begun trials by 1940, there were significant delays in actually getting it into production. The army had lost almost all its anti-tank guns in France, and with invasion seen as a real threat, it was decided to prioritise replacing them rather than bringing the new weapon into production.

It was an understandable decision – it was estimated that producing 100 new 6 pdrs would prevent the production of 600 replacement 2 pdrs – but the effect was to delay the start of 6 pdr production until November 1941 and its introduction into service until May 1942. By this point the 2 pdr – which was still equipping all British tanks in service – was well past its sell-by date, and British troops fighting in the desert had the unpleasant experience of watching their rounds skid off the upgraded armour of the German tanks they faced while well inside the effective ranges of the German's own long 50mm guns.

Rea Leakey describes this in action “We were disturbed to see our 2-pdr solid shots bouncing off their armour... When the action was over, I heard Milligan telling the other members of the crew that he had failed to brew up a single enemy tank, but thought he was shooting as accurately as ever before. He had not seen his shots bouncing off the targets, and I did not enlighten him” (2)

It is often said that as tanks were largely moved by rail, British tanks were disadvantaged by the narrow British railway loading gauge, which restricted the size of all tanks up to the Comet. It was certainly true that at 9 ft 6in the British loading gauge was significantly narrower than the 10ft 6in German equivalent.

However, it is also fair to note that the British did not make the best use of what was available to them. In particular, their commitment to firing on the move – a pre-war article of faith – meant that they mounted turret rings between the tracks to keep the centre of gravity low and facilitate this, rather than above them. This limited size of the turret ring, and thus the weapons the tank could mount. This is why the Churchill (for example) could not be upgraded to carry the powerful 17pdr, while the Sherman - a smaller vehicle overall, but with a turret ring above its tracks instead of between them – could de developed into the 17pdr Firefly.

This was not the only problem arising from the doctrine of firing on the move. The 2 Pdrs and even the early 6 pdrs were designed for “free elevation”, raised and lowered by a stock resting on the gunner's shoulder. The idea was that the gunner used his back and legs muscles to physically control the elevation of the weapon and keep it aligned on target, rather than the geared elevation used on later tanks.

This inevitably limited the size of weapon which could be mounted, but would supposedly allow tanks to fire accurately on the move, and pre-war regulars had often spent a good deal of time practising this.

Unfortunately, this proved completely impractical under actual combat conditions, and seriously reduced the accuracy of British tanks until they learnt to halt to fire as the Germans did, with the 1941 manual accepting that firing from stationery was more accurate and effective

Even when the British were able to shoe-horn the more capable 6 pdr into some existing tanks, the resulting cramped turrets meant losing the loader in the case of the Crusader and Valentine, leaving the remaining two turret crewmembers severely overworked. Only the Churchill upgrade, using a completely new and larger turret, was as successful as the equivalent German gunnery upgrades of the Panzer III & IV

The inadequacies of British tanks were worsened by problems with training, which further limited the effectiveness of their gunnery. Britain’s pre-war tank corps had been well trained but tiny, with very few trained crewmen. While the training schools were rapidly expanded, shortages of ammunition and even of space for gunnery ranges meant British gunners entered combat with significantly less experience than their opponents.

Michael Halstead recalled in 1940 “We didn't have much gunnery practice, only three 2-pounder rounds per man, but they gave one the feel of the business at last. I'm glad I didn't know then how puny this little gun was” (3)

Things did improve, but lack of space for firing ranges – especially once the build-up of US forces in Britain began after 1942 – meant that even in Normandy, most British crews had much less gunnery experience than their German opponents, which counted for a great deal in combat.

Once the 6 pdr did arrive, it offered significantly improved anti-armour performance, but the desert taught the British that enemy tanks were much less of a threat than anti-tank guns, especially if they could be dug in.

Engaging these with solid AP projectiles was futile, and machine gun fire was only effective from well inside the AT gun’s own range, making it a very unsatisfactory solution. Unfortunately, the HE round for the 6 pdr still contained only a small amount of explosive, significantly limiting its effectiveness. As a result, British tank units often had to rely on artillery to suppress or destroy anti-tank guns which they could not deal with themselves.

In this situation, the arrival of the US 75mm medium velocity gun – initially in a limited traverse hull mount on the M3 Lee / Grant then in a turret on the M4 Sherman – was enthusiastically received. Its AP round could deal with almost any German tank encountered in the theatre while its HE round contained more than twice the weight of explosive in the 6 Pdr HE, and was consequently much more effective.

Indeed, the desire for 75mm guns was such that some 120 6 pdr Churchill IVs were re-armed by replacing their entire mantlets with units from knocked-out Shermans (a complex conversion since the Sherman used a periscope sight rather than the simpler direct telescope of the Churchill) to create the Churchill NA 75.

It was then realised that as the high velocity 6 pdr was designed for higher bore pressures than the medium velocity 75mm, it could be bored out to take American 75mm ammunition without excessively weakening the barrel walls. The resulting 75mm weapon had the same external dimensions as the standard 6 pdr, and the two could be exchanged using a simple conversion kit.

Feedback about the 75mm from the desert and Italy was extremely positive. Indeed, in late 1942 Montgomery infamously declared that “the 75mm gun is all we require” (4).

Perhaps in response to this, the General Staff revised the policy on tank guns stated in mid 1942 where any future tank gun should be primarily an anti-tank weapon and effectiveness firing HE was important but secondary to a position by late 1942 whereby HE effectiveness was paramount, and AP capability was only required to deal with the types of German armour encountered to date.

This was not an unreasonable assumption – in December 1943 General Pip Roberts wrote in his “Notes on Armoured Division Tactics” of the 75mm “its great asset is that it can destroy anti-tank guns, not merely neutralise them but destroy them, and when we bear in mind that 75% of the fighting of an armoured division is against anti-tank you will realise that this is a very great asset” (5)

However, it did implicitly assume that the threats in Europe would resemble those in North Africa, and as we shall see, this did not prove to be entirely the case.

1. Peter Beale “Death by Design” 1998 P91

2. Rea Leakey “Leakey’s Luck” 1999 P63

3. Michael Halstead “Shots in the Sand” 1990 P25

4. Peter Beale “Death by Design” 1998 P97

5. Quoted in John Plant “Cruiser Tank Warfare” 2014 P186

British tank armament in the Second World War – Part 2

We saw in the first part of this article how experience in North Africa had taught the British that anti-tank guns were the primary killers of tanks, and the importance of having a good HE round to engage them.

This resulted in the US medium velocity 75mm gun fitted to the M4 Sherman being very well received, and an equivalent British weapon (essentially a bored-out 6 pdr (57mm) high velocity gun) was developed to fire the same ammunition.

Indeed, Montgomery infamously declared that “the 75mm gun is all we require” (6), though it is often overlooked that he said this in late 1942 and there is evidence opinion did change later even if he was reluctant to admit this in public.

This approval of the 75mm was not universal. In particular, while the 1943 General Staff policy called for a mix of three weapons - 75mm dual purpose (60%), 6 pdr (30%) and the new 95mm Close Support howitzer (10%) a paper from the Ministry of Supply argued that the 75mm actually represented an unsatisfactory compromise. It advocated a better policy might be 2/3 6 pdr or better high velocity weapons to deal with enemy tanks, and 1/3 95mm howitzers with powerful HE rounds.

Whether such a mix would have worked better remained untested, as the debate failed to produce a conclusion in time to amend production schedules for Normandy, after which point it was largely academic

The 95mm howitzer was a slightly odd weapon, using a shortened 3.7in AA barrel, the breech assembly of a 25 pdr and the recoil mechanism from a 6 pdr. As it was notably breech-heavy, a distinctive 152lb counterweight was fitted to the muzzle

It fired 25 pdr projectiles, modified to fit into a fixed cartridge case with a much lower velocity than the field artillery version. Two were issued to the HQ troop of each squadron and regiment, as with the earlier CS tanks.

They were intended to fire smoke or HE, and their larger HE rounds had around twice the explosive filling of 75mm rounds, with a consequent increase in their effectiveness.

However, by 1944 smoke was mostly being delivered by artillery and mortars. More to the point, with each squadron now having more than a dozen 75mm guns, one must question whether the slight additional weight of HE from the two specialised CS tanks really justified the complexity of yet another type of gun, with its attendant training and ammunition requirements. One can only assume not, since the requirement for a 95mm equivalent disappeared from the next generation of British tanks

Ironically, though the army had finally got the weapon it needed for the desert by the end of that campaign, the invasion of Normandy would be very different. The British were aware of the Panther, but initially assumed it would be used as a heavy tank like the Tigers met in Tunisia – difficult to deal with when met, but encountered only rarely and in small numbers.

As the invasion neared, it became clearer that the Panther in particular would be met in much larger numbers than previously expected, and that the 75mm AP round was largely ineffective against these vehicles

Just as importantly, the towed anti-tank guns which had caused such problems in the desert were increasingly replaced by self-propelled vehicles such as the StuG III, which might not be as well armoured as tanks but were much less vulnerable to the blast and shrapnel of HE rounds.

As a result, though most British tanks in Normandy would carry 75mm guns, 25% would retain 6 pdrs for its superior anti-tank performance – roughly typically one tank per troop.

However, standard 6 pdr AP rounds would struggle against the frontal armour of the newer German tanks, and once again, British tank crews found themselves at a significant disadvantage to their German opponents.

Montgomery was very reluctant to admit these problems in public, stating that the British had the measure of German armour and ruthlessly suppressing any contrary reports for fear of fuelling “Tiger-phobia”. In private, however, even he acknowledged that the British were outgunned.

The British had actually foreseen this potential problem in 1943, While an effective HE weapon remained the priority, and would be fitted to roughly 75% of tanks., they pursued three separate paths to develop better anti-armour weapons to equip the remaining 25% of vehicles.

Unfortunately, none of the three strands of development they embarked on were quite as successful as might have been hoped, or indeed reasonably expected.

The first was the development of improved Armour Piercing Discarding Sabot rounds for the 6 pdr. These contained dense tungsten penetrators within a light carrier that split apart at the muzzle (the “discarding sabot”) while the penetrator - much lighter and less affected by air resistance than a conventional round - flew onward. This gave much higher velocity - up to 1.5x the velocity of standard AP rounds - and dramatically increased armour penetration, putting the 6 pdr almost level with the 17 pdr until the latter gun also received APDS rounds later in the year.

However, the rounds had a number of shortcomings. They were only available in very limited numbers at first, typically only a few per tank, and arrived only just before D-day itself. As a result, there was neither the time nor the spare rounds to allow for adequate practice, which was especially necessary as the rounds’ higher velocity gave them a flatter trajectory and thus a different point of aim compared with the standard AP rounds crews were used to.

They were also inaccurate at ranges over 500m, and most importantly did not resolve the problem of the lack of a decent HE round for the 6 Pdr. However, Churchill units typically retained one 6 pdr armed tank in each three-tank troop, fulfilling the role that Fireflies fulfilled in Sherman units

The second scheme was a 1942 Vickers proposal to develop a high velocity long barrelled 75mm gun (actually a 76mm, but termed the 77mm to avoid confusion with the US 76mm) to arm the A27 Cromwell which was then under development, giving it much improved AT performance.

Unfortunately (and unbelievably) it was only discovered at a late stage that the resulting gun was too big to fit into the Cromwell, which then had to be armed with the British version of the 75mm medium velocity used on the Sherman.

Meanwhile, a new tank – the A34 Comet - was specified in 1943 to mount the 77mm, based on an enlarged and improved Cromwell. However, while this was undoubtedly best British tank of the war, the first examples only arrived in December 1944 and the type saw only limited action before the end of the war. This was especially frustrating since the Comet was no more technically advanced than the Cromwell, having similar suspension and identical Meteor engine, so there was no good reason why it could not have been produced instead had things been properly coordinated.

The final scheme, though perhaps the most obvious, was to design a new tank to carry the very powerful 17 pdr anti-tank gun, a very high velocity 76mm weapon which had appeared in prototype in 1942, and entered service in 1943. It was easily capable of killing any German tank the British would meet until the end of the war, but it was a very large and heavy weapon.

The tank initially expected to carry this weapon was the 45 ton Rolls-Royce designed A29. However, its 45 ton weight was seen as excessive, and it was cancelled in favour of the much lighter A30 Challenger – essentially a stretched Cromwell with an extra wheel station and an enlarged (but thinly armoured) turret containing two loaders (7). However, the Challenger did not arrive in Normandy until well after the initial landings, and was never really regarded as successful, with only 200 being built.

The situation was saved by the conversions of some standard Shermans to 17 pdr armed Fireflies, which began as an unofficial project like the Churchill NA75. 342 Fireflies were produced in time for D-day, so that one could be assigned to each Sherman troop.

As the 17 pdr lacked a good HE shell until after the Normandy campaign, however, they could never have become the main British tank even had they been available in sufficient numbers. This was especially true since they were as vulnerable as the standard Sherman, and suffered from low rate of fire due to excessive muzzle blast and difficulty of handling the large rounds in the cramped turret. However, they provided a much-needed boost to the firepower of Sherman equipped regiments which formed the majority of British armour in Normandy.

Interestingly, despite the ad hoc attempts to up-armour vehicles with spare track links frequently seen in north-west Europe, 21st Army Group operational research concluded that up-armouring British tanks would only have limited benefits, given the powerful tank guns in German service by then.,

The report concluded that the best way to increase their survivability was actually to increase their firepower - destroying opposing vehicles quicker and at longer ranges would significantly decrease the number of hits the Allied vehicles took in the process.

It is sometimes asked why the British did not make use of the 3.7in AA gun as a tank weapon, in the same way as the Germans used the famous 88mm, especially since British AA crews had actually practised using their weapons in an anti-tank role during their annual practice shoots until 1937.

The answer is two-fold. First and simplest, they didn't need to do so, since the 17 pdr was entirely capable of dealing with any contemporary German tank without requiring the same weight and size inside the turret. Indeed, it is arguable that mounting the 88mm on the Tiger was actually a mistake by the Germans, since the long 75mm / L70 used on the Panther could deal with any Allied tank, and it was originally agreed during the design stage that most of the Tiger production run would mount what effectively became the Panther turret.

Second, the British actually did begin developing a tank-mounted version of the 3.7in in September 1943, as a follow-on to the 17 pdr. The resulting 94mm weapon weapon was designated as the “Ordnance QF 32 Pdr”; it was investigated (unsuccessfully) as a gun for the cancelled A43 Black Prince and actually installed on the six A39 Tortoise prototypes.

British tank designs used straight tube telescopic gunsights, which created a weakness where they pierced the mantlet and required the gunner to move his head significantly as the gun elevated or depressed. By contrast, US designs used periscope sights above the turret roof, which did not pierce the mantlet and required less head movement during elevation, but could be knocked out of alignment with the gun. German gunsights had the best quality optics, and used a telescopic with an optical hinge so the eyepiece remained stationery whatever the gun did, and an armour plate prevented anything striking the outer lens from continuing into the gunner's eye

Like the other Allied powers, Britain stuck with mechanically-struck percussion primers to initiate tank guns; only the Germans made general use of electrical primers, which improved accuracy by reducing the lag between the trigger being pulled and the gun firing.

Both the British and Soviets favoured electrical turret traverse systems over the hydraulic systems used by the Americans, partly because of the high fire risk from the inflammable hydraulic fluid. The Germans used both types, but allied tanks generally had faster traverse systems, giving them a limited advantage

Overall, it is fair to say that in the early years of the war, the major problem with British tanks was mechanical unreliability, with inadequate firepower a close second. The reliability issues were largely resolved by 1943, but apart from a short period after the initial appearance of the 75mm, the problem of inadequate firepower persisted to the end of the war.

The problem was not the guns themselves, but developing tanks capable of carrying them. It seems obvious that one should design a tank to mount a particular gun, but in practice this only really happened with the A34 Comet and A41 Centurion, both at the end of the war. Previously, tanks appeared to receive whatever gun was available, even if it was clearly not ideal for the current threat, which is why Britain ended up with six different tanks all mounting the same 2 pdr gun in production at the same time.

The situation was not helped by organisational structures. Tank guns (like all other guns) fell under the Director General of Artillery, rather than the tank division of the Ministry of Supply or the Department of Tank Design.

In fairness, the holder of this post often proved quite forward-thinking. For example, he initiated work on the 17 pdr in the expectation that it would be necessary to counter improving German armour well in advance of a formal GS requirement for such a weapon

However, poor coordination between tank and gun design resulted in a long period (almost 2 ½ years) between the initiation and design of the 17 pdr in April 1941 and inception of design of the first tank designed from the ground up to carry it (the Centurion) in November 1943.

It was worsened by the delay in reacting to changing requirements – having spent the early part of the war with a weapon optimised for AP when they needed HE, British soldiers in Normandy found themselves with plentiful HE capability but in desperate need of more and better anti-tank firepower.

In fairness, it was not only British tank designs which were under-gunned. Until the arrival of the 90mm armed M26 Pershing very late in the war, US tank units were actually even wore off, as they had the same over-dependence on the medium-velocity 75mm, and the US 76mm which replaced it was less capable than the British 17 pdr

6. Peter Beale “Death by Design” 1998 P97

7. It was never really clear why two loaders were felt necessary, since the Firefly and indeed the 88mm armed German Tiger seemed perfectly capable of operating with only one