Shooting the War

Artillery Guns of the WWII

Running parallel with this unfolding story of piercing projectiles was the development of the hollow-charge principle into a viable weapon. This illustrates the adaptation of a well-documented scientific phenomenon to a weapon of war: almost 200 years ago a Norwegian engineer had observed that hollowing out the face of an explosive charge made it cut deeper into rock when blasting. In the 1880s an American experimenter, Monroe, found that when firing guncotton slabs against armour plate, the initials ‘USN’ engraved in the guncotton reproduced themselves in mirror-like form in the face of the armour plate. From his observations and reports the phenomenon became known as the ‘Monroe Effect’ and was a scientific curiosity for many years. Just before the First World War one or two inventors toyed with the idea of employing this effect in mines and torpedoes, but since no one really understood why it did what it did, it was difficult to engineer the idea into a practical form.
Just before the Second World War broke out, a Swiss consortium approached the British government to offer a ‘new and powerful explosive’ for anti-tank use—at a high price. The inventors refused to divulge any information until cash was forthcoming, but were prepared to demonstrate their projectile being fired. An astute observer from the Research Department of Woolwich Arsenal went to Switzerland to watch the firing; being a well-read expert on ammunition development and history, he realised that what he was watching was not a new and powerful explosive so much as a practical application of the Monroe Effect. Upon his return to Woolwich he duly reported this, and, since it appeared that the Monroe Effect could be made to work, research immediately began into applying it to a light anti-tank grenade which the infantry soldier could fire from his rifle. Before the outbreak of war, this ‘68 Grenade’ had been perfected and was in production, and carries the distinction of being the first weapon ever to reach the hands of troops which relied on the Monroe Effect, or as it came to be known, the Hollow-Charge Principle.
What is this Hollow-Charge Principle? Put simply, it consists of forming the forward surface of the shell’s explosive charge into a cone or hemisphere and then lining this with a thin metal liner. The shell is then fitted with a suitably shaped nose, for ballistic effect and also to give the vital ’stand-off’ distance. This is the distance from the target—a matter of a few inches—at which the explosive must be detonated in order for the hollow charge to work effectively. On detonating the explosive at its rear end, the detonation wave exerts an immense pressure on the metal of the liner; the cone shape virtually’focusses’the explosive energy and causes the metal of the liner to be shaped into a jet of finely-divided metal and explosive gas, shooting toward the target at speeds of up to 20,000 feet per second. The stand-off distance is necessary in order to allow this jet to form and accelerate. When the jet strikes the target plate, the pressure exerted is so great as to blast a hole through the armour, blowing splinters of metal from the inside and permitting the white-hot jet to pass into the tank where it will set fire to fuel or ammunition, and, of course, kill or injure the crew.
The great virtue of the hollow-charge shell is that its performance is always the same, irrespective of the velocity at which it strikes. Even if the shell were standing still when detonated, the penetration would be the same. Because of this, it could be fired from guns too small to fire the large cartridges needed to give the necessary velocity to normal piercing projectiles. As soon as the 68 Grenade was seen to be successful, design began on other hollow-charge projectiles. A great deal of work went into producing one for the 25-pounder, though in the end it was never issued, since the AP shot issued for that gun was quite satisfactory and there was no real need for a hollow-charge shell. Then came a request from India to produce an anti-tank projectile for the 3.7-inch Pack Howitzer, the modern version of Kipling’s immortal ’screw-gun’. This gun, a small and portable weapon, could not be made to fire a piercing projectile at anything like the velocity needed to defeat even Japanese tanks, and a hollow-charge shell was designed and placed in production. The same shell was used in the 95-mm howitzer, an abortive infantry support gun which never saw service as a towed weapon, though it was employed as a self-propelled support weapon by the Royal Marines in Normandy and by the Armoured Corps.
By 1944, though, sufficient basic research had been done into this principle for it to be seen that a spinning shell was not the ideal method of employing hollow charges, since the spin tended to spread the jet out and give poor penetration. Finned projectiles were more effective, and consequently no more artillery shells were designed around the hollow charge; it was extensively employed, instead, for infantry weapons such as the PIAT, the Bazooka, and a variety of rifle grenades.
The Germans, and later the Russians, embraced the hollow-charge shell wholeheartedly. The Germans began issuing shell in late 1940 and eventually almost every German field and tank weapon had a hollow-charge shell, thus giving every gun or howitzer an anti-tank capability. Indeed, so short were the Germans of anti-tank guns after the Russian invasion got under way, that they hastily collected up all the French army’s 75-mm guns and assembled hundreds of them on to redundant anti-tank gun carriages of German design. A hollow-charge shell was produced and these makeshift weapons were deployed in Russia to stem the advancing Soviet tanks until 75-mm and 88-mm anti-tank guns were in sufficient supply. Judging from appearances, the Soviet hollow-charge shells were developed as virtual copies of German designs which had been captured.
In addition to artillery shell Germany also used the principle for infantry weapons such as the Panzerfaust, rifle grenades, and even a small shell which could be fired from a signal pistol. They also employed the principle in an ingenious attempt to prolong the life of the prewar 37-mm anti-tank gun, whose piercing projectile was, by 1942, no longer effective against current tanks. A large hollow-charge bomb was fitted with a hollow tail carrying fins; within this tail was a stick which fitted snugly into the barrel of the 37-mm gun, allowing the tail and fins to slide over the barrel. A blank cartridge completed the outfit, and this was used to fire the stick bomb to ranges of 300 to 400 yards. The bomb’s warhead was about 6 inches in diameter and carried about 8 pounds of explosive, giving a devastating effect at the target. In all fairness, it must be pointed out that Lieutenant-Colonel Blacker, inventor of the PIAT and the `Black Bombard’ of Home Guard fame, had proposed a similar 60-pound stick bomb in 1940, to be fired from the 25-pounder, but the idea was turned down on the grounds that it might lead to misemployment of the gun as a purely anti-tank weapon. (This misemployment theme was not confined to the British side: many German Flak commanders bewailed the loss of their valuable 88-mm Flak guns as they were whittled away to provide anti-tank defences.)
The third subject is the application of new principles to gun design. The first of these to be unveiled was the taper-bore antitank gun, which has already been touched upon. This was the child of a German engineer called Gerlich, who, advocating his principle of attaining high velocity without attracting any buyers, had been stumping the world for several years. He was briefly employed by both the US War Department and the British War Office at various times, but his ideas on improving shoulder arms were felt to be impractical. He eventually settled in Germany and saw his idea accepted as an anti-tank weapon. The 28/21-mm came first, then a 42/30-mm and finally a 75/50-mm. Unfortunately, the lack of tungsten carbide for the special projectiles spelled the demise of these weapons, but experiments continued with coned bores and coned muzzle-adapters for guns of various calibres up to as large as 280-mm, in order to boost velocity and range. These were intended to use high-explosive shells, which were more practical in the larger calibres, though the development of a shell which would stand up to being squeezed down the gun barrel was no easy task.
The second, and more widespread, new line of thought was the recoilless gun. Like most weapon ideas, there was nothing really new about it: Commander Davis of the US Navy had produced a recoilless (RCL for short) gun during the First World War which was adopted by Britain as an anti-Zeppelin aircraft weapon. The virtue of an RCL gun is that by having no recoil one needs no complicated hydraulic buffer system to absorb the firing shock: one need only make the gun-carriage strong enough to take the weight of the gun, instead of being strong enough to withstand being fired from—an ideal state of affairs for an aircraft weapon, particularly in the stick-and-string era. Davis’s idea is worth looking at, although outside our time scale, since it is the classic recoilless weapon. He simply provided the gun with two barrels, one pointing forward which fired a normal shell, and one pointing rearward which fired an identical weight of grease and buckshot. When the central cartridge was fired the shell and countershot departed at equal speed in opposite directions and cancelled each other’s recoil. From this it can be seen that if you make the countershot (say) one-fifth of the weight of the shell and fire it out at five times the speed, then the gun will still be in balance. Taking this idea to its logical conclusion one finishes up firing out of the back of the gun a fast, light stream of gas, still balancing the recoil since the weight times speed of the gas is the same as the (greater) weight times (slower) speed of the shell.
Cutting down the recoil
This was the principle which the Germans revealed in Crete when their troops appeared armed with a 75-mm RCL gun. The shell was the standard 75-mm shell, but the cartridge case had a frangible plastic base which held for long enough to allow pressure to build up and start the shell moving, then blew out through a hole in the breech-block, releasing the balancing stream of gas. The all-up weight of the gun, on its ex-machine gun tripod, was only 320 pounds, whereas the weight of the standard 75-mm field gun was about 11/2 tons—no mean saving for airborne carriage. A 105-mm version soon followed, weighing 855 pounds as opposed to the 105-mm 1E FH18’s 4,312 pounds, and many more developments began in this field to provide light weapons for mountain troops and infantry, particularly for anti-tank use. (It ought perhaps to be pointed out that the Panzerfaust was in fact a recoilless gun, and not, as generally supposed, a rocket launcher). Eventually RCL guns of up to 380-mm calibre were under development, including many for slinging beneath aircraft to carry artillery aloft for the battle against the Allied bombers, but none of these came to fruition.

n Britain, the RCL gun development during the war is a scarcely-known story of one man’s persistence. Sir Denis Burney, airship designer and prolific inventor-engineer, began to be interested in the recoilless principle early in the war. In order to prove his theories he converted a four-bore gun into a recoilless weapon and proceeded to fire it from the shoulder with ease; it must have been the world’s most comfortable duck gun. Having proved his point he proceeded to design a series of RCL guns ranging from 20-mm to 8-inch calibre. In addition to designing the guns, he expanded his theories and designed special ammunition to take advantage of the ballistic peculiarities of the weapon. He argued that since the rearward blast was taking place, the pressure within the gun would be less than with a conventional type, and the shell would be subjected to a more steady thrust. In which case it would be possible to make shells with thinner walls, which would carry greater charges of explosive than previously possible. He then went further, and reasoned that, since the shell walls were thin, if the shell were to be filled with the then new plastic explosive, it would spread on to the surface of the target like butter; a fuse fitted in the base of the shell would then detonate this plaster and blast in the target. His envisaged target was either the concrete emplacements of the European coast, or the palm-reinforced Japanese bunker, and he called his shell the Mal I buster’.
In 1944 his designs were accepted and a 3.45-inch (the same calibre as the 25-pounder) shoulder-fired gun, a 3.7-inch towed gun, a 95-mm towed howitzer, and a 7.2-inch towed howitzer were prepared for production. The 95-mm was also jeep-mounted—the first application of what has since become a standard method of carrying these guns. The 7.2-inch soon fell by the wayside, since it had been intended solely as a means of defeating the Atlantic Wall emplacements, but other weapons were found to do all that was needed. The 3.45-inch was intended as an infantry weapon in the jungle, enabling one man to carry what was virtually a 25-pounder punch on his shoulder. The 3.7-inch was proposed as the future infantry anti-tank weapon, and the 95-mm was contemplated as the airborne field gun to replace the US 75-mm howitzer and the 25-pounder. However, before the guns were produced in sufficient quantity for issue, the war came to an end; some 3.45-inch and 3.7-inch guns were issued to selected infantry units to obtain their reaction to RCL guns as a general thing, and the 95-mm was abandoned altogether.
The principal difference between the Burney guns and the German type was that the Burneys had much longer barrels, and used cartridge cases which, instead of the plastic blow-out base, used many perforations in the sidewall to release the gas into a surrounding chamber, from whence it was passed back to a number of vents around the breech.
Concurrently with Burney’s work in Britain, American designers began on similar weapons. A 105-mm howitzer T-9 was developed on similar lines to the German 105-mm, having a blow-out base to the cartridge. Another team developed 57-mm and 75-mm weapons which used perforated cases similar to the Burney pattern but having more and smaller holes, and also had the shell driving band pre-engraved in order to reduce the pressure inside the gun. Both these latter weapons were accepted for service early in 1945, saw service with the US Army in the Pacific theatre, and remained in service for many years. A third team, this time under the auspices of the National Research and Development Council, developed a 4.2-inch RCL mortar, an unlikely-sounding weapon which so as to be able to fire direct at the target at low angles, carried a small rocket on the nose of the shell to push it down the barrel’and fire the propelling cartridge in the usual mortar fashion. Due to the blast of the rearward jet, it could only be fired at low elevations; there was a certain amount of enthusiasm for this weapon but it never entered service.
Perhaps the best summing up of all wartime development on RCL weapons was made in a wartime report: ‘Undoubtedly a number of effective recoilless weapons have been developed, but they are being accepted with reserve, and will only be considered as supplementary to older and more orthodox weapons which have proved their accuracy and reliability in service.’
There is, unfortunately, no space here to delve into more recondite stories of research and development: the British 13.5-inch gun linered-down to 8-inch calibre which, fired from Dover, reached a range of over 100,000 yards; the British and American development of flying artillery, which culminated in the mounting of a 32-pounder anti-tank gun in a Mosquito; the German V-3 multiple-chamber gun which was intended to shell London; the American 36-inch mortar ‘Little David’, designed to batter Japanese strong-points; the German rocket-assisted and ramjet-assisted heavy artillery shells which promised vast increases in range; or the Anglo-American development of the electronic proximity fuse which proved the answer to both ‘Doodlebugs’ and kamikaze pilots. These and similar stories may only interest the specialist, but they, together with what has been written here, serve to illustrate the incredible range of inventions brought into play in the war waged between the designers and inventors of each side, each endeavouring to get one step ahead of the other, if only temporarily.

The German Super-Guns of the WWII

The German super-guns
The heaviest field equipments seen during the war were the German self-propelled howitzers generically known as ‘Karl Morsers’. These were of two calibres, 540-mm and 600-mm, mounted on the same type of carriage. Six carriages were made and the exact disposition of barrels between them is in some doubt; the carriages were numbered I to VI; Vehicle V was captured by the US 1st Army and found to have a 540-mm barrel, yet photographs captured later showed this same carriage to have a 600-mm barrel. It is probably safe to assume that three of each calibre were made. The date of introduction is also a little vague, but it seems fairly certain that the 600-mm version was introduced in 1942 and the 540-mm in 1944.
The carriage of ‘Karl’ was a simple rectangular box, divided into three compartments. The first held the Mercedes-Benz engine and transmission; the second carried the gun; and the third held the carriage raising and lowering gear. After driving into position on its tracks the engine was used to drive the lowering gear, which rotated the anchorages of the suspension torsion bars so as to allow the chassis to be lowered to the ground until the suspension and track were relieved of the weight. For long-distance moves the gun and recoil system were removed from the carriage, dismantled, and loaded on to spec,a -,a e•s, the carriage was then winched on to a special tank-transpor-er. For very long distances the complete gun and carriage assembly could be slung between two railway flat wagons by means of special trusses.
In the use of railway artillery Germany virtually had the field to herself. This class of weapon is really the prerogative of the Continental nation with a well-developed rail system by which it can readily deploy them to any front. In contrast, Britain and the USA, while possessing railway guns. used them solely as mobile coast defence units, since the problem of transporting two or three hundred tons of railway mounting across the Channel was not a trick to be undertaken lightly. Indeed, the British and American weapons were almost entirely relics of the First World War which had been in mothballs. 1940 saw a few more mountings hastily cobbled together from available spares and hurried to cover the Channel, just as in similar fashion American guns were mobilised and deployed in 1941. In 1944 reports from France indicated that heavy railway artillery might be of use in demolishing strongpoints to be expected in the final assault in Germany, and designs were hastily prepared by the Americans for a number of 16-inch guns, but within a few weeks it was seen that heavy artillery of this class had been rendered superfluous by the quality and quantity of air support available, and the demand was cancelled.
The German army had a vast range of railway guns from 150-mm upwards, but two were really outstanding and deserve closer examination. The first was the 28-cm K5(E)—Kanone, Model 5, Eisenbahnlafette —which became their standard super-heavy railway gun and was probably the finest design of its k;nd in the world. The basic arithmetic and paperwork had been done in the late 1920s and early 1930s, and work began on the gun in 1934. (It is worth noting that every German railway gun was designed and built by Krupp— Rheinmettal did design two, but they were never made.) First, a 150-mm barrel was produced for tests; it had been decided that to obtain the great range demanded, a conventionally rifled barrel was out of the question. A design was prepared with 12 deep grooves and having a shell carrying 12 ribs, or splines, to match. The theory behind this was that the engraving of a conventional copper driving band on the shell gave rise to very high pressure in the gun chamber; by using the spline and groove method to spin the shell, this resistance was removed, and the shell would step off more smartly, allowing a bigger propelling charge to be used without over-straining the gun. The 150-mm test barrel proved that the theory was right, and a full-calibre 280-mm barrel was built.
The mounting was a simple box-girder assembly carried on two six-axle bogies, with the front bogie slung so as to allow the front of the box-girder to be swung across it for aiming the gun. For large angles the whole weapon was mounted on a special portable turntable built at the end of a short spur of track laid at the desired firing point. Each gun was supplied with a special train which included wagons for carrying the turntable, light-antiaircraft guns for local defence, air-conditioned ammunition wagons, living quarters and kitchen for the gunners, and flat wagons to carry their entitlement of motor transport.
By 1940 eight of these complete equipments were in service, and production continued throughout the war, 25 being built in all. The German gunners called them ‘Slim Bertha’, but to the Allies in Italy one at least became famous as ‘Anzio Annie’.
With the 561-pound pre-rifled shell the gun could reach to 68,000 yards. A rocket-assisted shell was later developed which increased this range, with a certain loss of accuracy, to 94,000 yards. Finally, the Peenembride Research Establishment designed a 300-pound dart-like projectile which was fired from a special 310-mm smooth-bore barrel and which ranged to 170,000 yards. Although coming too late for general issue, these ‘PeenemOnde Arrow Shells’ were issued for troop trials in the field, and some were fired against the US 3rd Army at ranges of about 70 miles.
The second railway gun, ‘Gustav’, was the biggest gun the world has ever seen —the Krupp-designed 800-mm Kanone. The idea was conceived in 1937 of a pair of super-guns; they were of quite conventional design, except for their immense size. Too large to be moved in one piece, they were transported piecemeal in special trains and assembled at the selected sites by travelling cranes. When assembled, the mounting straddled two sets of standard-gauge rails, with 80 wheels taking the 1,350-ton weight. An armour or concrete-piercing shell of 7 tons was propelled by a 13/4-ton charge to a range of 23 miles, or a 5-ton high-explosive shell to 29 miles. The first equipment, ‘Gustav’, was proved at the Rugenwalde range in March 1943, in Hitler’s presence. The only record of its use was at the siege of Sebastopol; the gun was sited at Bakhchisary and fired some 30 to 40 rounds. One shot is recorded as having penetrated through 100 feet of earth to destroy a Soviet ammunition dump at Severnaya Bay. The subsquent history of the gun is unknown (it was presumably captured by the Red Army).
The second equipment, ‘Dora’. so far as is known, never left the proving ground, though what happened to it at the end of the war is a minor mystery (some ammunition and a spare barrel were found at Krupp’s proof establishment at Meppen near the Dutch border).
The detachment necessary to man. maintain, and give local protection to Gustav was 4,120 men strong. commanded by a major-general. The actual fire-control and operation of the gun demanded a colonel and 500 men, and the construction or dismantling of the weapon took between four and six weeks. A long-range ‘PeenemOnde Arrow Shell’ was developed for Gustay. but, so far as is known, was never fired. This was to weigh 2.200 pounds and range to 100 miles. There was also a proposition to mount a 520-mm gun on the same carriage to fire rocket-assisted shells and ‘PeenemOnde Arrow Shells’ to a range of 118 miles for cross-channel bombardment, but this never got past the drawing-board.
If it is accepted that it is not a good idea to tamper with a good gun design in the middle of a war, then the only way to render the gun more effective is to improve the ammunition, and this technique was frequently adopted during the war. And in no field is this seen to greater effect than in the battle against the tank. The reason for this is fairly self-evident: personnel targets remain more or less the same—once the anti-personnel projectile is perfected it can stay as it is. On the other hand, once a new anti-tank projectile appears, it is only a matter of time before the enemy put thicker armour on his tanks.
At the outbreak of war there were two types of anti-tank projectile: the armour-piercing (AP) shot, and the AP shell. The difference is basic. Shot are solid, with no explosive filling, and rely purely on their speed to smash through the armour and do damage inside the tank by their impact, the fragments of plate they knock off during penetration, and their own effect when they penetrate the plate and bounce around inside the tank. AP shells, on the other hand, have a small cavity filled with high explosive and are fitted with a fuse in the base. The shell penetrates, similarly to shot, by brute force, but the fuse is activated by the impact and, after a short delay to allow the shell to pass through the plate and enter the tank, the explosive is detonated, shattering the shell into fragments and adding to the shot-like damage already caused. On paper the shell is the better proposition, since there is the bonus of the explosive filling. But paper figures tend to be deceptive, and in fact the shot is probably the more practical projectile, because the high-explosive (HE) cavity weakens the shell, and the fuse is precariously supported against the hammer-blow of impact. Britain held firmly to the shot theory for anti-tank work, though many years of experience in producing AP shells for naval use was available. Several other nations preferred AP shell, bewitched by the HE bonus.
Most of the belligerents entered the war with a plain shot or shell and relied on throwing it hard enough to penetrate the opposing tanks. So long as the target was relatively lightly armoured this was successful; but, naturally, each side began to increase armour thickness on each succeeding generation of tank. The quick answer to this was to increase the gun charge or even the calibre, and thus throw the projectile harder, but there comes a time when the impact is too much for the projectile, and instead of piercing, it merely shatters on the outside of the target without doing any damage.
The answer to this was to protect the tip of the shot or shell with a softer cap, which tended to spread the impact stresses over the shoulders of the projectile, instead of concentrating them into the tip. This preserved the piercing action to higher velocities, and the gun was again winning the battle. The next move belonged to the tank designers who made their armour thicker, and so it went on until the projectile was once more shattering, cap or no cap. At this point the projectile designers were faced with a new problem: if it was futile to throw the projectile harder, might it not be possible to throw a harder projectile? And what was harder than an armour-piercing projectile? Tungsten carbide, a diamond-hard alloy, provided an answer, but it was about one-and-a-half times as heavy as steel, so that it could not easily be made into a projectile. Furthermore, it was expensive and in short supply.
The first application of tungsten to an anti-tank projectile was by the German army in their 28-mm Schwere Panzerbuchse 41, a weapon with a unique tapered barrel. The shot consisted of a small core of tungsten carbide held in a light alloy casing of 28-mm calibre. As the shot was fired down the gun barrel, so the calibre diminished and the light alloy casing was ground down, until it emerged as a 21-mm shot. This squeezing enhanced the velocity and changed the ratio of shot diameter to weight. The velocity reached was 4,000 feet per second, and, on impact with the target, the hardness of the core was impervious to impact shock and penetrated successfully.
About the same time—late 1940—a similar idea had been put forward by a Mr Janacek, a Czechoslovakian weapon designer working in England. While his idea was still under consideration, a specimen of the German weapon was captured in North Africa and flown home for trials: the idea was seen to be feasible. The British version was in the form of a taper-bore adapter to be fitted to the existing 2-pounder gun, together with a special tungsten-cored shot, known under the code name of ‘Littlejohn’, an Anglicised version of Janacek. The advantage here was that the adapter could be removed to permit firing normal explosive shells, but could be refitted quickly for the special shot, whereas the German design required a special pattern of high-explosive shell to be developed, a difficult feat in such a small calibre. The ‘Littlejohn’ attachment and its shot were not used in towed artillery, since by the time they were ready for service the anti-tank units were armed with 6-pounders, but it was used on 2-pounder and American 37-mm guns mounted in armoured cars.
To use tungsten in a conventional gun, a different approach was needed. The first attempt, for the 6-pounder, was the ‘AP Composite Rigid’ (APCR) shot, a tungsten core mounted in an alloy sheath of approximately the same dimensions as the conventional steel shot for the gun. By virtue of its light alloy content the APCR shot was somewhat lighter and thus had a higher velocity when fired. Unfortunately the ratio of weight-to-diameter was unfavourable, giving a poor ballistic coefficient or ‘carrying power’, and while the short-range performance was impressive, the velocity soon dropped, and at ranges over 1,000 yards, steel shot was just as good, sometimes better. Some German weapons were also provided with the same type of projectile, and one was designed for use in the Soviet 76.2-mm field gun which the Germans captured in large numbers and converted into an anti-tank gun. Unfortunately for them, by early 1942 the shortage of tungsten in Germany began to be felt, and in the middle of that year a ban was placed on the use of tungsten in ammunition; what scarce supplies there were had been earmarked for machine tool production, not for throwing about the Russian steppes. After strong remonstrations, the 5-cm Pak 38 anti-tank gun was specifically exempted from this ban, since at that time it was the only weapon capable of stopping a Russian T-34 tank, provided it was supplied with tungsten-cored shot.
Although the 6-pounder APCR shot seemed reasonably successful, it was not the ideal answer. The ideal, in fact, sounded ridiculous: what was wanted was a shot which in the barrel was large-calibre and light, so as to pick up speed quickly and leave the gun at high velocity, but which outside the barrel should be small in diameter and heavy, so as to have good ‘carrying power’ and keep up its high velocity for a long range. These two conflicting requirements were fused into one projectile by two British designers, Permutter and Coppock, of the Armaments Research Department. Even before the 6-pounder had received its APCR shot they were at work, and in March 1944 their ‘AP Discarding Sabot’ shot was provided for the 6-pounder. In this design, the tungsten core is contained in a streamlined steel sheath or sub-projectile; this in turn is carried in a light-alloy framework or ’sabot’ of the full gun calibre. On firing, this sabot holds the sub-projectile centralised in the bore and gives the whole thing the combination of light weight and large area which is wanted for velocity. But firing actually ‘unlocks’ the sabot, and as the shot leaves the gun muzzle, so the sabot is thrown clear, allowing the sub-projectile to race to the target at velocities of the order of 3,000 feet per second. Now, since the sub-projectile’s sheath is virtually a skin round the tungsten core, it follows that the weight is high in relation to the cross-section—the ideal condition for good carrying power and thus long-range performance. A similar projectile for the 17-pounder followed in September 1944, and one was under development for the 20-pounder tank gun when the war ended.

The Germans concentrated their armour from the start in special armoured divisions comprising a balanced force of tanks, artillery, infantry, engineers, and administrative services. No consideration was given to the idea behind the French and British ‘infantry’ tanks and the doctrines associated with them. The tanks, supported by their own artillery and infantry, were to operate as a concentrated strategic force directed against the enemy’s weakest spots and well ahead of the main, slower, infantry army.
This tank army, trained as a team, consisting of ten armoured divisions by May 9, 1940, contained at all levels a wealth of experience. Many of its officers and men were members of tank units which fought on Franco’s side in the Spanish Civil War. Here they gained battle practice: they tested new techniques and the mechanical capabilities of their machines; and they saw the fate that befell tank forces that were put into battle dispersed in ‘penny packets’. Moreover, intensive peacetime exercises in Germany had been supplemented by the bloodless occupations of Austria in 1938 and Czechoslovakia in 1939. In rapid, long-distance thrusts through these countries, the armoured forces taught themselves essential administrative lessons without having actually to engage in combat.
In September 1939, when the fighting began, the administration worked well and the armoured divisions outfought the old-fashioned Polish army in a matter of days, showing that the quality of the highly specialised, mechanised forces was master of the quantity mustered by the larger, traditional conscript armies. It also confirmed what had been long understood: that the air arm, working in close cooperation with tanks, conferred a powerful element of heavy fire-support on forces operating deep in the enemy rear. The aircraft were in fact a substitute for heavy artillery.
Singers without song
Thus on May 9, 1940, the relative overall condition of the opposing armoured forces can be summarised as follows. The French, saddled with a technique that was 20 years out of date, and with machines operated by men who lacked experience of the pace and scope of modern battle conditions, were partnered by the British, whose techniques were far more up-to-date, but who were attempting to practise them with too few machines, and with a number of officers and men who had not yet had time to grasp the significance of their new role. Indeed, it was this lack of experience that most seriously bedevilled the fighting quality of the Allies. Their armoured formations, either through reasons of policy, doctrine, or lack of machines, had not practised together. Nor was there close co-operation with the air arm in the forefront of the land battle. So they were in fact singers without a song.
Fatally linked with their limited use of tanks was the failure of the Allied command to understand and make adequate strategic preparations to defeat the German attacks when they eventually came. There was a belief, sincerely held, despite warnings from men of practical experience, that some terrains were naturally tank-proof and others could be made secure by the erection of concrete and steel fortifications. It was thought that mechanised armies would not be able to pass through the narrow lanes, forests, and valleys of the Ardennes; that the Maginot Line would be impenetrable, and that the extensions of the Maginot Line along the Belgian frontier, certain inundations, and large built-up areas would also be serious obstacles to tank action.
Therefore the Allies made no elaborate plans for tank counterthrusts in the localities they had classified as tank-proof. The best, mobile armoured portions of the French army were not deployed in a manner permitting them to launch an immediate, concentrated counterstroke —even if their doctrine had envisaged such action. As we have seen, no such doctrine existed and as a result it was quite conceivable —even probable—that the light mechanised divisions and the new tank divisions could be flung in piecemeal (and therefore outnumbered) against superior enemy formations.
Their opponents, the Germans, lacked neither doctrine, equipment, training, nor experience. They were masters of a new war-winning technique that brought speed and mobility to the battlefield. By a combination of speed, thrust, and shock action they could bring a completely new momentum to the battle. The impact of the German armoured divisions could not be compared with that of the basically cavalry- and infantry-oriented methods of the Allies: they had in fact — with their range and striking power —introduced a new dimension to warfare.
Types of tank
Yet inevitably the balance of material was in favour of the Allies, who had more tanks than the Germans and many that were technically superior. In their ten armoured divisions the Germans had only 627 of the good Mark III and IV tanks, armed respectively with a 37-mm and a 75-mm gun, and protected by armour not more than 30-mm in thickness. The remaining 2,060 tanks were lightly armoured machines, mostly armed only with a 20-mm gun — although 381 of these were the sound Czech light T-38, equipped with a 37-mm gun. In addition to the 2,690 tanks with the armoured divisions, there were some 800 machines, mostly light ones, in reserve.
Against this array the French fielded about 3,000 machines, of which 500 were in units in the course of formation, plus older reserve machines. Of these 3,000 tanks, 1,292 were with the light mechanised divisions and the new tank divisions; the remainder were split up among the infantry armies. To this total should be added the British. On May 9 they had in France
210 light tanks in the light armoured regiments, and 100 ‘1′ tanks in the lst Army Tank Brigade. A further 174 light tanks and 156 of the new cruisers, belonging to the Armoured Division, were ready to cross the Channel as the battle started. Thus the Allies could oppose 3,000 German tanks with something like 3,600 of their own — if they chose.
On balance, the quality of the machines possessed by the two sides was about equal. The best French tank, the Char B, mounted the excellent 47-mm gun in a fully rotating turret and had a 75-mm gun mounted in the hull. The 20-ton Somua had a 47-mm gun, too, and was fast. The armour of these tanks was from 40 to 60 mm thick, compared with the best German armour of 30 mm. There were 800 of these new machines and even the older ones compared well with the German lighter vehicles. The 384 light British tanks were certain to be severely outclassed in a stand-up fight, because their guns could not penetrate armour, although their high speed and small size might serve them well when engaged on reconnaissance. But the 100 infantry tanks, of which 23 were the new Matilda, were covered by immensely thick armour (up to 70 mm) and quite safe from the fire of the German tank guns. And the 2-pounder gun, mounted in the thinner cruisers of the Armoured Division and also on the Matilda, was a weapon capable of penetrating any of the German machines at battle ranges.
But while the German and British machines (with one exception) were designed with two- or three-man turrets, the French machines had a single man in the turret confronted with the difficult task of commanding the vehicle, loading and firing the gun, and sometimes controlling the tactics of sub-units. The single British exception was the Mark I infantry tank, and this too presented terrible problems of combat efficiency and command.
This technical factor meant that the German and most of the British crews would be able to fight as teams within the all-embracing organisation of the armoured formations to which they belonged—but would also give the Germans an important advantage when their tank formations clashed with the French. This would make up for the fact that the majority of their tanks were vulnerable to the enemy tank guns, while their own guns would not penetrate the armour of a large proportion of the Allied tanks.
Leadership
The importance of personal command and direction is far more apparent to the fighting man in a climate of military opinion that insists that the generals should remain in the fore-front of the battle, in close touch with the leading tanks both visually and by radio. The Germans practised this method more than the Allies. The French kept their command posts further to the rear in accordance with the practice of 1918, and in any case did not possess a control system suited to high-speed combat. This fact, when combined with the separation of the tank-crew commander from the rest of his crew, would be liable to foster a drop in morale among the French tank units (there is evidence to support this —noted by British tank crews working alongside the French later in the campaign). It was clear, they said, that when faced by German tanks the French crews became cautious and were almost paralysed; and this exaggerated respect for the enemy was a result of the drubbing they had received in their first encounters with the German tanks. Even if the balance of morale between the contestants was equal on May 9, a week later the defects in organisation, leadership, and tactics had swung the scales irrevocably in favour of the Germans.
The overriding superiority of the Germans over the Allies was inherent in their intention to make use of well co-ordinated, massed, all-arms formations, launched into battle at the critical points, commanded by inspired men of vision and determination. Men of the stamp of Guderian and Reinhardt led the armoured corps from the van of the battle (with Rommel leading one of the divisions) — and this wealth of talent could not fail to overwhelm lesser men with old-fashioned ideas. For on the Allied side, none of the generals of 1940 had
•    deep knowledge of armoured warfare; with
•    startling lack of foresight, those men who had made a study of the subject had been distributed to positions where their talents lay unused. Martel commanded an infantry division; Broad, Pile, and Lindsay had been sent—some say deliberately—to posts unconnected with armoured warfare; and Hobart had been removed from the Active List, though he was ultimately to be recalled. De Gaulle was only just in the process of assembling a brand new and totally inexperienced tank division.
Let it be admitted that men such as these were not easy to live with. They had learned to be ruthless in the face of long-established tradition, that out-dated rules must be broken whatever the personal and immediate consequences, and that these circumstances applied in all armies. Men insufficiently imbued with spirit failed in the face of military ‘vested interests’; those who stood up to them but were unblessed by fortune were removed—as Hobart was; those who fought, and were lucky, followed their stars to success in war in the forefront of the armoured battle.
In 1940, it was the Germans whose spirit and good fortune had combined — and so they dominated. Most of the French armoured commanders were ineffective, and the grossly outnumbered British tank men could not, except on one outstanding occasion, make a decisive contribution.
In numbers the Allies were superior to the Germans; in quality of equipment they were, on balance, about equal; in strategic and tactical application, they were markedly inferior.
The sheer superiority of German armoured technique ensured the certainty of their victory before the frontiers were crossed.