PIAT

1. Lead

The PIAT — the Projector, Infantry, Anti-Tank — was the British Army’s infantry anti-tank weapon of the Second World War, and one of the strangest weapons ever issued to soldiers. It was not a rocket launcher, like the American bazooka or the German Panzerfaust, and it was not a rifle, like the Boys anti-tank rifle it replaced.

It was a spigot mortar, powered by a large spring and a small propellant charge, which fired a hollow-charge bomb that could penetrate the armour of a German tank at short range. It was heavy, at about 15 kilograms, it was hard to cock, it kicked violently, and its bomb arced through the air like a mortar shell — but it worked, and it gave British infantry, for the first time in the war, a weapon that could kill a tank.

The PIAT was used in North Africa, in Italy, in Normandy and at Arnhem, where it won six Victoria Crosses, and it remained in British service until the early 1950s.

The PIAT’s story is the story of British infantry anti-tank warfare: a story of improvisation, of a weapon designed in a hurry by a man who had never designed a weapon before, and of soldiers who learned to use it because they had nothing better. The weapon was designed by Lieutenant Colonel Stuart Blacker, a British officer who had served in the First World War, and it was developed by Major Millis Jefferis, the head of the War Office’s experimental establishment, who turned Blacker’s idea into a weapon that could be mass-produced. This article describes the PIAT’s background and development, its design, its variants, its operational history, its performance, its operators, its legacy and the examples that survive.

2. Key Facts

Type	Infantry anti-tank projector (spigot mortar)
Origin	United Kingdom
Designers	Lieutenant Colonel Stuart Blacker; Major Millis Jefferis
Manufacturer	Imperial Chemical Industries and others
In service	1942–early 1950s (British Army)
Produced	1942–1945; about 115,000 built
Weight	About 15 kg (32 lb) unloaded; about 16.4 kg (36 lb) loaded
Length	About 0.99 m (39 in)
Calibre	83 mm bomb (3.25 in)
Bomb weight	About 1.36 kg (3 lb)
Muzzle velocity	About 76 m/s (250 ft/s)
Effective range	About 110 m (120 yd) against tanks; about 320 m (350 yd) maximum
Penetration	About 100 mm (4 in) of armour (hollow charge)
Rate of fire	About 4–5 rounds per minute
Crew	2 (gunner and loader)
Most famous action	Arnhem, September 1944 — six Victoria Crosses involving the PIAT

3. Background and Development

The Boys rifle and its failure

The PIAT was born of the failure of the Boys anti-tank rifle, the British Army’s infantry anti-tank weapon at the start of the Second World War. The Boys was a large, heavy bolt-action rifle, firing a 13.9 mm armour-piercing bullet, and it had been designed in the 1930s to penetrate the armour of the light tanks of the time.

By 1940, it was obsolete: German tanks had thicker armour, and the Boys could not penetrate it at any range, and it was so heavy and so violent to fire that soldiers hated it. In France in 1940, British infantry armed with the Boys found that they could not stop German tanks, and the Army urgently needed a replacement.

The replacement had to be light enough for a soldier to carry, powerful enough to penetrate a tank’s armour, and simple enough to be mass-produced in wartime Britain — and it had to be designed quickly, because the Army needed it at once.

Blacker and the spigot mortar

The replacement was designed by Lieutenant Colonel Stuart Blacker, a British officer who had served in the First World War and who had, in the 1930s, designed a spigot mortar — a weapon in which the bomb sits on a spigot, a rod, rather than in a barrel, and is propelled by a charge in its tail.

Blacker’s idea was to use a large spring to drive the spigot forward, and a small propellant charge in the bomb to complete the launch, producing a weapon that had no recoil in the conventional sense and that could fire a large, hollow-charge bomb from a short, light tube.

The idea was ingenious and, at first, it did not work: the spring was hard to cock, the bomb was inaccurate, and the weapon was dangerous to its user. But Major Millis Jefferis, the head of the War Office’s experimental establishment at MD1 — known as “Winston’s Toy Shop” — saw the idea’s potential, and he and his team turned Blacker’s prototype into a weapon that could be mass-produced.

The PIAT was adopted in 1942 and entered service in 1943.

Mass production

The PIAT was mass-produced by Imperial Chemical Industries and by other British firms, and about 115,000 were built between 1942 and 1945. The weapon was issued to British infantry platoons — one PIAT per platoon, with a gunner and a loader — and to Commonwealth forces, including the Canadians, Australians and New Zealanders, and to the Home Guard, the Free French, and the resistance movements in occupied Europe.

The PIAT’s production was a triumph of wartime improvisation: the weapon was made from steel tubing, a spring, and a simple trigger mechanism, and it could be built in factories that had never made weapons before. The bomb, a hollow-charge projectile with a shaped-charge warhead, was also mass-produced, and millions of rounds were made.

The PIAT was, in short, a weapon that Britain could build in large numbers, quickly, and that gave its infantry a chance against tanks.

4. Design

How the spigot mortar worked

The PIAT was a spigot mortar, and its operation was unlike any other infantry weapon. The bomb, a hollow-charge projectile weighing about 1.36 kilograms, sat on a spigot — a steel rod — at the front of the weapon, with its tail tube fitting over the spigot.

When the trigger was pulled, a large spring drove the spigot forward, striking the propellant charge in the bomb’s tail and firing the bomb from the weapon. The spring then recoiled, and the weapon had to be recocked by the gunner, who stood on the weapon’s butt and pulled the body upwards, compressing the spring — a task that required considerable strength and that was, in the words of one soldier, “like trying to close a giant mousetrap with your feet”.

The bomb left the weapon at a muzzle velocity of about 76 metres per second, arced through the air like a mortar shell, and struck its target with a hollow-charge warhead that, on detonation, formed a jet of molten metal that penetrated the armour.

The hollow-charge bomb

The PIAT’s bomb was a hollow-charge, or shaped-charge, projectile, and it was the key to the weapon’s effectiveness. A shaped charge works not by kinetic energy — by the speed and mass of the projectile — but by the explosive itself: on detonation, the explosive collapses a copper cone in the nose of the bomb into a jet of molten metal, travelling at several kilometres per second, which punches a small hole through armour and sprays hot metal and fragments into the tank’s interior.

The PIAT’s bomb could penetrate about 100 millimetres of armour — enough to defeat the side and rear armour of a German Panzer IV or Panther, and the frontal armour of lighter tanks — and it did so regardless of the bomb’s velocity, which meant that the weapon’s low muzzle velocity did not matter.

The bomb’s weakness was its accuracy: the low velocity and the arcing trajectory made it hard to hit a moving tank at more than about 100 metres, and the bomb’s fuse sometimes failed if it struck at too shallow an angle.

Weight, recoil and the gunner’s burden

The PIAT weighed about 15 kilograms unloaded and about 16.4 kilograms loaded, and it was 0.99 metres long — heavy and bulky for an infantry weapon, and a burden for the gunner who had to carry it, with its bombs, across country.

The weapon’s recoil was violent: the spring and the propellant charge together produced a kick that could bruise the gunner’s shoulder and that made accurate shooting difficult, and the weapon’s muzzle blast was large and visible, revealing the gunner’s position.

The PIAT’s sights were simple — a front post and a rear aperture — and the weapon was fired from the shoulder or from the ground, with the gunner lying prone or kneeling. The crew was two men, a gunner and a loader, who carried the bombs in a satchel, and the weapon’s rate of fire was about four to five rounds per minute, limited by the time it took to recock the spring and to load the next bomb.

5. Variants

Variant	Years	Key features
PIAT Mk I	1942–1945	Production model; spigot mortar; 83 mm hollow-charge bomb
PIAT (training)	1943–1945	Inert practice bombs; drill rounds for training
PIAT (Home Guard)	1943–1945	Issued to Home Guard units; same weapon, different markings
PIAT (post-war)	1945–early 1950s	Continued in British service; replaced by the 3.5-in rocket launcher and later by the Carl Gustaf

One weapon, no variants

The PIAT was produced in a single main variant, the Mk I, with small changes during production: the sights, the butt pad and the trigger mechanism were improved, and the bomb’s fuse was changed to make it more reliable, but the weapon itself remained the same from 1942 to 1945.

There were no calibre changes, no lightweight version, and no vehicle-mounted version in British service, although the PIAT was sometimes fired from the back of a truck or from a building, and its bomb was also used as a demolition charge by engineers. The weapon’s uniformity was a strength: a soldier trained on one PIAT could use any other, and a bomb made for one weapon fitted them all.

The PIAT’s only real variant was the training round — an inert bomb, filled with sand or with a smoke marker, that allowed soldiers to practise without using a live hollow-charge bomb.

The bomb and its uses

The PIAT’s bomb was also used for purposes other than anti-tank work. The hollow-charge bomb could be used against bunkers, pillboxes and buildings, where its shaped charge punched a hole through concrete or brick, and the weapon was sometimes used as a short-range mortar, firing its bomb in a high arc at targets behind cover.

The bomb’s versatility was a consequence of its design: a shaped charge works against any armour, whether steel or concrete, and the PIAT’s low velocity and arcing trajectory made it useful for firing over walls and into windows. The weapon’s crews learned to use it in ways its designers had not intended, and the PIAT became, in the hands of experienced soldiers, a general-purpose infantry weapon, not merely an anti-tank weapon.

Replacement

The PIAT remained in British service until the early 1950s, when it was replaced by the 3.5-inch rocket launcher — the British version of the American bazooka — and later by the Swedish Carl Gustaf recoilless rifle. The replacement was a recognition that the PIAT’s design, ingenious as it was, had reached its limits: the spring was hard to cock, the bomb was slow and inaccurate, and the weapon was heavy for what it could do.

The rocket launcher and the recoilless rifle were lighter, faster and more accurate, and they became the standard infantry anti-tank weapons of the post-war British Army. The PIAT’s replacement did not diminish its wartime record: it had given British infantry a weapon that could kill a tank, and it had done so at a moment when no other weapon could.

6. Operational History

North Africa and Italy

The PIAT first saw action in North Africa, in 1943, where British infantry used it against German and Italian tanks in Tunisia, and it proved its worth at once: the hollow-charge bomb could penetrate the armour of a Panzer III or Panzer IV, and the weapon’s short range — about 100 metres — was less of a disadvantage in the close country of Tunisia than it would have been in the open desert.

In Italy, from 1943 to 1945, the PIAT was used in the close fighting of the mountains and the towns, where tanks and infantry fought at short range and where the PIAT’s ability to fire from a building or from behind a wall made it invaluable.

The weapon’s crews learned to wait until a tank was close, to fire from cover, and to fire again before the tank’s crew could reply — tactics that required courage, because the gunner had to expose himself to fire the weapon, and that worked because the PIAT’s bomb, when it hit, killed the tank.

Normandy

The landings and the bocage

In Normandy, in June 1944, the PIAT was the British infantry’s principal anti-tank weapon, and it was used in the landings and in the fighting that followed. The weapon’s short range was a disadvantage in the open country of Normandy, but it was an advantage in the bocage — the hedgerow country of Normandy, where tanks and infantry fought at ranges of a few dozen metres and where the PIAT’s ability to fire from behind a hedge made it deadly.

British infantry armed with the PIAT destroyed German tanks at Villers-Bocage, at Caen, and in the fighting for the Falaise Pocket, and the weapon’s crews earned a reputation for courage: the PIAT gunner had to stand up, aim, and fire, in full view of the tank he was trying to kill, and he had to do it at a range at which the tank’s machine gun could kill him.

The weapon’s record in Normandy was a record of men who accepted that risk and who, more often than not, killed the tank.

Arnhem and the Victoria Crosses

The PIAT’s most famous action was at Arnhem, in September 1944, during Operation Market Garden, where British paratroopers of the 1st Airborne Division, surrounded by German tanks and cut off from relief, used the PIAT to hold off German armour for nine days.

The paratroopers, armed with the PIAT and with little else that could kill a tank, destroyed German tanks in the streets of Arnhem and at the bridge, and their PIAT gunners earned six Victoria Crosses — the highest British award for gallantry — in actions involving the PIAT, more than for any other single weapon in the war.

The most famous of the six was Major Robert Cain, of the 2nd Battalion, South Staffordshire Regiment, who, on 21 September 1944, single-handedly destroyed a German tank with a PIAT, and then, when the tank’s crew abandoned it, destroyed another, and who continued to fight with the PIAT for days, despite being wounded.

Cain received the Victoria Cross, and the PIAT’s part in his story made the weapon a legend in the British Army.

The end of the war

In the last months of the war, the PIAT was used in the fighting in the Netherlands, in Germany, and in the Far East, where British and Commonwealth infantry used it against Japanese tanks and bunkers. The weapon’s record in the Far East was less distinguished than its record in Europe, because Japanese tanks were lightly armoured and the PIAT’s hollow-charge bomb was more than enough to kill them, but the weapon’s short range and heavy weight were a disadvantage in the jungle, where infantry had to carry everything they used.

The PIAT’s war ended in 1945, with the surrender of Germany and Japan, and the weapon was, by then, the most decorated infantry anti-tank weapon in the British Army — a weapon that had, in the words of one historian, “given the infantry a chance, and the infantry had taken it”.

Losses and cost

The PIAT’s cost was paid in the lives of its gunners. The weapon’s short range and its visible muzzle blast meant that the gunner had to expose himself to fire the weapon, and that the tank he was trying to kill could kill him first. The PIAT’s crews suffered heavy casualties in Normandy and at Arnhem, where the weapon’s gunners were among the first to be targeted by German tanks and infantry. The weapon’s record is therefore a record of both remarkable success and remarkable sacrifice, and the six Victoria Crosses won with the PIAT at Arnhem are a measure of the courage the weapon demanded — and of the courage the men who used it showed.

The PIAT’s casualties were not limited to Normandy and Arnhem. In Italy, in the Netherlands, and in Germany, PIAT gunners were among the first to be targeted by German tanks and infantry, because a PIAT gunner, standing to fire, was visible and vulnerable, and because a tank’s crew knew that the man with the PIAT was the man who could kill them. The weapon’s crews accepted that risk, and they did so because they knew that, without the PIAT, their platoon had no defence against a tank at all.

7. Performance and Specifications

Specifications in full

The figures in the table below are the standard PIAT figures, taken from British Army manuals and from post-war studies. The penetration figure of about 100 millimetres is the figure for the hollow-charge bomb against rolled homogeneous armour at 90 degrees, and it varied with the angle of impact and with the condition of the bomb.

The effective range of about 110 metres against tanks was the range at which a trained gunner could expect to hit a tank-sized target; the maximum range of about 320 metres was the range at which the bomb could be fired as a mortar, against a large target such as a building.

The muzzle velocity of about 76 metres per second was low by the standards of any other infantry weapon, and it was the reason the bomb’s trajectory arced and the reason the weapon was inaccurate at long range.

Specification	PIAT
Weight (unloaded)	About 15 kg (32 lb)
Weight (loaded)	About 16.4 kg (36 lb)
Length	About 0.99 m (39 in)
Calibre (bomb)	83 mm (3.25 in)
Bomb weight	About 1.36 kg (3 lb)
Muzzle velocity	About 76 m/s (250 ft/s)
Effective range (anti-tank)	About 110 m (120 yd)
Maximum range	About 320 m (350 yd)
Penetration	About 100 mm (4 in)
Rate of fire	About 4–5 rounds per minute
Crew	2 (gunner and loader)
Production	About 115,000

Comparison with other anti-tank weapons

Compared with the American bazooka, the PIAT was heavier — 15 kilograms against the bazooka’s 6 kilograms — and shorter-ranged, at about 110 metres against the bazooka’s 140 metres, but it had no back blast, which meant it could be fired from inside a building or from a trench, where the bazooka’s rocket exhaust would have killed its crew.

Compared with the German Panzerfaust, the PIAT was heavier and more complex, but it was reusable, while the Panzerfaust was a single-shot, disposable weapon. Compared with the Boys rifle it replaced, the PIAT was a revolution: the Boys could not penetrate a tank’s armour at any range, while the PIAT could penetrate 100 millimetres, and the Boys was a rifle, while the PIAT was a weapon that could kill a tank.

In its own time, the PIAT was the best infantry anti-tank weapon the British Army had, and its record — six Victoria Crosses at Arnhem — is the best measure of what it could do in the hands of brave men.

8. Operators

The British Army and the Commonwealth

The PIAT was built for the British Army, which operated it from 1942 until the early 1950s, and which issued it to every infantry platoon — one PIAT per platoon, with a gunner and a loader — and to the airborne forces, the commandos, and the Home Guard.

The weapon was also issued to the Commonwealth forces — the Canadians, Australians, New Zealanders, South Africans and Indians — who used it in North Africa, Italy, Normandy and the Far East, and who, like the British, found it heavy, hard to cock, and effective.

The Canadians, in particular, used the PIAT extensively in Normandy, where their infantry destroyed German tanks with it at Caen and at the Falaise Pocket, and the Australians used it in the Pacific, where it was effective against Japanese bunkers and light tanks.

Other operators

The PIAT was also issued to the Free French forces, to the Polish forces in exile, and to the resistance movements in occupied Europe, where it was dropped by parachute to the French Resistance, the Dutch Resistance, and the Yugoslav Partisans.

The weapon’s lack of back blast made it ideal for resistance fighters, who could fire it from inside a building or from a cellar, and its simple design made it easy to maintain with few tools. After the war, the PIAT was used by the Israeli forces in the 1948 Arab-Israeli War, by the Indian Army, and by other armies that had received it as military aid.

The weapon’s widespread use, in so many armies and in so many theatres, is a measure of how widely the British Army’s improvisation was shared — and of how many soldiers, in how many countries, owed their lives to a spring-powered mortar designed in a hurry in 1941.

9. Legacy and Influence

The weapon that gave infantry a chance

The PIAT’s legacy is the six Victoria Crosses won with it at Arnhem, and the reputation it earned as the weapon that gave British infantry a chance against tanks. Before the PIAT, British infantry had no weapon that could kill a tank; after the PIAT, they had one, and they used it, in North Africa, in Italy, in Normandy and at Arnhem, to destroy German tanks that would otherwise have overrun them.

The weapon’s design — a spigot mortar, powered by a spring — was never repeated, and it remains unique in the history of infantry weapons, but its principle — the hollow-charge bomb, which penetrates armour regardless of velocity — became the standard for infantry anti-tank weapons after the war, and it is still the principle behind the rocket launchers and recoilless rifles that infantry use today.

The human legacy

The PIAT also left a human legacy. The weapon’s gunners — the men who stood up, aimed, and fired, in full view of the tank they were trying to kill — are remembered in the British Army as among the bravest soldiers of the war, and the six Victoria Crosses won with the PIAT at Arnhem are a measure of the courage the weapon demanded.

Major Robert Cain, who destroyed two German tanks with a PIAT at Arnhem and who continued to fight for days despite being wounded, is remembered as one of the great heroes of the British Army, and his story is still told to young soldiers as an example of what a single man, with a simple weapon, can do.

The PIAT’s story is, in the end, a story of men, not of a weapon: of the men who designed it in a hurry, of the men who built it in factories that had never made weapons, and of the men who used it, at short range and at great risk, to kill tanks.

10. Surviving Examples

Museums in Britain

Several PIATs survive in museums in Britain, and they are among the most accessible Second World War weapons a visitor can see. The Imperial War Museum in London holds a PIAT, with its bombs, and the National Army Museum in London holds another, with a display explaining how the spigot mortar worked.

The Airborne Assault Museum at Duxford holds a PIAT used at Arnhem, and the Royal Armouries at Leeds holds a PIAT in its collection of infantry weapons. These weapons are displayed with their bombs, their sights, and their spring mechanisms, and a visitor can see, at a glance, how strange the weapon was — a steel tube, a spring, and a bomb on a spigot — and how simple it was, for all its strangeness.

Survivors abroad and visiting them

Outside Britain, PIATs survive in museums in Canada, Australia, New Zealand and the Netherlands, where they are displayed as part of the story of the Commonwealth forces and of the Arnhem battle. The Airborne Museum at Oosterbeek, in the Netherlands, holds a PIAT used at Arnhem, and the Canadian War Museum in Ottawa holds a PIAT used by Canadian infantry in Normandy.

For anyone who wants to understand the PIAT, a visit to the Imperial War Museum in London or to the Airborne Museum at Oosterbeek is the best introduction there is, because both museums display the weapon with its bombs and with the story of the men who used it — and because both museums let a visitor see, at close range, the weapon that won six Victoria Crosses at Arnhem.

Frequently Asked Questions

What is the PIAT?
The PIAT — Projector, Infantry, Anti-Tank — was the British Army’s infantry anti-tank weapon of the Second World War. It was a spigot mortar, powered by a spring, firing an 83 mm hollow-charge bomb that could penetrate about 100 mm of armour.

How did the PIAT work?
A large spring drove a spigot forward, striking the propellant charge in the bomb’s tail and firing the bomb. The gunner then recocked the spring by standing on the butt and pulling the body upwards. The bomb’s hollow-charge warhead penetrated armour on impact.

What did the PIAT replace?
The PIAT replaced the Boys anti-tank rifle, which by 1940 could not penetrate German tank armour at any range. The PIAT could penetrate about 100 mm of armour.

How many Victoria Crosses were won with the PIAT?
Six Victoria Crosses were won in actions involving the PIAT at Arnhem in September 1944, more than for any other single weapon in the war. The most famous was Major Robert Cain, who destroyed two German tanks with a PIAT.

What was the PIAT’s effective range?
About 110 metres against tanks. Its maximum range, fired as a mortar, was about 320 metres. Its low muzzle velocity of about 76 m/s made it inaccurate at longer ranges.

Where can I see a PIAT today?
The Imperial War Museum in London, the National Army Museum in London, the Airborne Assault Museum at Duxford, and the Airborne Museum at Oosterbeek in the Netherlands all hold PIATs.

Related articles

• 44M Tas Tank
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• Balao-class Submarine

Sources

1. Wikipedia, “PIAT” — spigot mortar, specifications, penetration of about 100 mm, Arnhem, six Victoria Crosses.
2. Ian Hogg, British and American Artillery of World War 2 (Greenhill Books, 2002) — PIAT design and performance.
3. Chris Bishop, The Encyclopedia of Weapons of World War II (Barnes & Noble, 1998) — PIAT, bazooka and Panzerfaust comparison.
4. Imperial War Museum, London — PIAT exhibits and Arnhem displays.
5. Martin Middlebrook, Arnhem 1944: The Airborne Battle (Viking, 1994) — PIAT at Arnhem and Robert Cain.
6. British Army manuals, Small Arms Training: PIAT (War Office, 1943) — operation, cocking and firing drill.