The PIAT, for Projector, Infantry, Anti Tank, was one of the earlier anti-tank weapons based on a HEAT shell. It was developed by the British starting in 1941, reaching the field in time for the invasion of Sicily in 1943. Due to the nature of the projectile and length of the weapon, the PIAT could be used more easily in enclosed spaces than the American bazooka or its German copy, the Panzerschreck, which made it more useful in close-combat and for urban warfare.
One problem reported with the PIAT was that the bombs it fired were quite sensitive, due to the special firing mechanism, and if dropped could explode. Hence some bombs were given special caps over the ignition device to prevent this. The bomb had to be positioned correctly or it would not fire and would have to be removed, the gun re-cocked taking time before it could be fired again.
At the start of World War II, all major armies were investing in research into HEAT to produce an infantry weapon capable of defeating modern armor. The US and Germans concentrated on rockets to propel their weapons, but in 1941 when the PIAT was being developed, these systems were nowhere near ready for use.
The British instead turned to a prewar weapon known as the Blacker Bombard, a large mortar type of weapon, known as a "spigot discharger" or spigot mortar, invented by Lt-Col Blacker, RA. The Bombard consisted of a heavy "barrel" containing a large spring. The spring pushed against a 12 pound (5 kg) steel canister and rod that rode up the barrel and struck the rear of the bomb, igniting a small propulsion charge. The heavy bolt and rod, known as the spigot, was used primarily to damp out the recoil of the round leaving the barrel. The charge was also intended to reset the spring, meaning that the weapon had to be cocked only once, by pulling up on the tube while standing on a handle mounted at the rear.
The Blacker Bombard was never used operationally, and was retained for use by the Home Guard. However the design was suitable for modification as the launcher for a HEAT round. The drop in size of warhead required (an effective HEAT shell was 3 lb compared to the 20 lb HE used on the Bombard) meant that the PIAT would be much lighter and maneuvreable than the Bombard's 150 kg mass. A section of the "barrel" was cut away on the top to form a tray for the round, which could be reloaded with fresh rounds with the operator remaining prone. The charge on the shell was small enough that it caused no real smoke or backblast, a significant advantage over the bazooka. However, the heavy duty spring and spigot pushed the weight up, resulting in a weapon that weighed 34 pounds (15 kg) unloaded. Furthermore, if the charge failed to reset the spigot, which happened often enough (especially when the firer could not take the recoil), the operator had to retire behind cover to re-cock the weapon. This required a 200 pound pull, and to get the necessary pull the user needed to stand up.
In general use the PIAT had a rated range of about 100 m, but that was considered the extreme and it was typically fired at much shorter ranges. The three pound (1.4 kg) HEAT warhead was able to penetrate about 100 mm of armor at 100 m. This was too little to defeat the frontal armor of the newer German designs, but remained effective against side and rear armor. The PIAT could also function in a mortar-like role, where the shell was fired in a parabolic arc up to 350 m. The PIAT was also widely used in the "house-breaking" role, being fired into a room near the proposed assault team's entrance.
An attachement that allowed the PIAT to fire 2in mortar shells, was produced in limited numbers.
Private Ernest Alvia "Smokey" Smith of the Seaforth Highlanders of Canada earned the Victoria Cross after crawling to within ten metres of a Panther to destroy it with a PIAT.
In one of the most remarkable examples of bravery under fire, Major Robert Henry Cain also earned the Victoria Cross at Arnhem during Operation Market Garden. Using a PIAT gun (in addition to several other weapons) he destroyed or disabled six tanks, four of which were Tigers, as well as a number of self-propelled guns.
The PIAT remained the main British platoon-level anti-tank weapon until 1950, when it was replaced by the US M20 Super Bazooka, known as Launcher, Rocket, 3.5 inch UK (M20) in British service and then later by the ubiquitous Carl Gustav recoilless rifle.
The naval weapon Hedgehog was another application of the spigot discharger principle.
Anti-tank weapons | World War II British infantry weapons | Mortars | Military Equipment of the British Empire
Projector Infantry Anti Tank | פיאט (כלי נשק) | PIAT | Granatnik przeciwpancerny PIAT | PIAT | PIAT