With the large loss of anti-tank weaponry at the Battle of Dunkirk in northern France, the British were forced to develop all-new, modern anti-tank measures for expected German invasion of the British mainland. The PIAT ("Projector, Infantry, Anti-Tank") was the offspring of rather hurried design and development period, bypassing much of the hard testing usually done by British Army authorities concerning such weapons. The PIAT made use of a "hollow charge" projectile which was launched from a spring-loaded, tube-shaped launcher and became a proven commodity against all known enemy armor types of the day - despite the unit's cumbersome handling qualities and dangerous recoil forces. The weapon was typically crewed by two personnel though it could be just as effective under the direction of one if need be and went on to become one of the most famous anti-tank weapons of the war alongside well-known contemporaries such as the German "Panzerschreck" and American "Bazooka". The PIAT saw considerable use with British forces and found homes in the inventories of Australia, Canada, France (Free French), Greece, India, Israel (post-war), Italy (post-1943), Luxembourg, New Zealand, Poland (by resistance forces), the Soviet Union (via Lend-Lease) and Yugoslavia. It was effective against any of the lighter German vehicles and could stop a Panzer IV and Panther tank while also able to disable even the mighty Tiger I heavy tank (as it did during the engagement at Arnhem). Prior to the arrival of the PIAT, the primary anti-tank weapon used by the British Army was the Boys Anti-Tank Rifle to which the PIAT succeeded and saw frontline service from 1942 to 1950.
Despite its intended use as an anti-armor weapon by way of its High-Explosive, Anti-Tank (HEAT) standard projectile, the tactical value of the PIAT was slightly greater than that of the famous Panzerschreck and Bazooka for it was also cleared to fire a High-Explosive (HE) grenade and a smoke version - the former useful against "soft" targets such as infantry while the latter holding value as an effective smoke screen to cover movements by friendly forces or shroud enemy vision. The PIAT also became a low-cost weapon that could be produced quickly during a time desperation for the British Empire. It did, however, serve its faults for the PIAT held a clunky, rigorous reloading scheme and was bulky to manage in the heat of battle at 32lbs with a 3lb projectile. Engagement ranges reached out to approximately 370 yards though effective ranges were within 110 yards and typically shorter for sure "kill". Such ranges forced the PIAT crew to remain dangerously close to their intended target. It was at these short ranges, however, that the PIAT's strength shown through with its armor-defeating qualities. It proved particularly effective in the close confines of urban warfare where hidden PIAT crews certainly held an edge against unsuspecting enemy tank crews.
As built, the PIAT measured a length of 3 feet and each projectile featured a 2.5lb hollow charge filling designed for impact detonation. The grenades exited the launcher at 250 feet per second and sighting was accomplished through an aperture device affixed to the upper left side of the weapon. The PIAT's general shape was tubular with a shoulder pad fitted to the rear and an open "trough", or tray, held at the front. The compressed spring, the heart of the PIAT's action, was contained in the body with a rudimentary trigger system slung underneath. An adjustable monopod was installed ahead of the trigger group for forward support. Grenades were fed into the open trough at the front and the system actuated by the trigger in the usual way.
Production of PIATs was charged to Imperial Chemical Industries Ltd and manufacture was soon joined by others as the need for anti-tank weapons grew. Final approval for the weapon came on August 31st, 1942 and some 115,000 examples then followed. The design was attributed to Major Millis Jefferis who headed the Ministry of Supply, delving into the development of "special" weapons for the British military. Another notable, unorthodox weapon brought to light by this group became the "Sticky Bomb", otherwise known as the "Grenade, Hand, Anti-Tank No. 74" or "S.T. Grenade".
While other global militaries had settled on rocket-propelled grenades (chemical energy) for their anti-tank solution, the British Army's adoption of the PIAT was unusual in that the weapon relied on the "spigot mortar" principle requiring no complex rocket function or launching properties, keeping production costs in check and manufacture numbers steady. Basic operation involved the main spring interacting with a centrally-positioned spigot which fit inside the hollowed tail of the grenade projectile. The operator unlatched the shoulder pad and held it down with his feet with the muzzle of the weapon pointed upwards. The body of the PIAT was then pulled up which moved both spring and spigot to an awaiting sear. The body could then be lowered to the shoulder pad, the pad re-latched and the system considered "cocked" (the process was reminiscent of a medieval crossbow). Now that the internal main spring was fully compressed, ready produce a substantial amount of force, a projectile was inserted into the awaiting trough. Once the trigger was pulled and the spring released, the resulting action activated the grenade's propellant charge. The resulting detonation served two purposes - it launched the projectile clear of the trough and onto its flight path while the recoil force was used to re-cock the main spring to ready the weapon for a successive shot. If the weapon failed to re-cock for whatever reason, the crew needed to manually reset the spring once more - this could prove detrimental as a standing PIAT man made for a clear target to enemy infantry. It was often recommended that two persons assist in the cocking of the weapon, such were the physical forces in play.
Unlike the Panzerschreck and Bazooka, the PIAT was not a true shoulder-fired weapon but instead set along the ground or atop a raised natural/structural support on its given monopod. The butt was then held firmly against the shoulder prior to firing. A standing operator could suffer serious physical injury due to the inherently violent recoil action of the weapon. The adjustable nature of the monopod allowed for a wide range of trajectories to be reached.
The spigot mortar concept was not a new one as it already circulated in the British inventory through the 29mm "Blacker Bombard" anti-tank mortar device. The Blacker Bombard was the brainchild of one Lt Col Stewart Blacker and developed in the early stages of World War 2, primarily issued to Home Guard units who lacked proper tank-stopping weaponry. The platform served beginning in 1941 and utilized the same launching principle as the PIAT. Some 22,000 were produced and some issue occurred in the ranks of both the Army and Royal Navy.
It was this weapon that lay the foundation for the famous PIAT series for it was actually born of The PIAT was actually born of Blacker's work when he attempted to develop a handier, portable version that came to be known as the "Baby Bombard". When Blacker left for another position, Jefferis continued work on the weapon which was given the designation of "Bombard Baby, 0.625 inch No. 1" during trials with the Ordnance Board.
The British Army was the sole mainstream adopter of a spigot mortar-type weapon for all others chose to accept rocket-propelled forms in time. Beyond its low complexity and low-cost nature, such weapons, inherently gave off no smoke from a launching projectile, keeping the crew's position safe from spotters. Additionally, no rocket propulsion meant that there was no back-blast to injure allies positioned aft of the weapon, allowed the weapon to fire relatively safely from confined spaces.
PIAT systems were issued beyond standard anti-tank formations and many were used by light armored vehicle groups for self-defense or ambush. Some tracked carriers were outfitted with up to 14 PIATs atop a special mounting to form an ad hoc mortar system in-the-field. Not an entirely popular weapon, the PIAT certainly filled a role and filled it effectively. First use of the weapon came from Canadian forces during the invasion of Sicily of July 1943 and the weapon did not disappoint. British elements found similar success during their romp through northern France following the D-Day landings of June 1944. The success of weapons such as the PIAT forced the Germans to increase use of armored skirts to protect their vital track components. A stranded tank was a sitting duck for artillery, anti-tank cannon or infantry ready to grenade and gun down the crew inside.
The British Army eventually followed many Western forces when it adopted the American Bazooka and it was this weapon that officially ended the PIAT's reign. Israel fielded the weapon during the 1948 War of Independence and some PIATs were still in circulation during the upcoming Korean War (1950-1953) by Australia.
The base long form PIAT designation was "Projector, Infantry, Anti-Tank MK I".