PIAT rubber butt pad, New Old Stock (Original unused). The Projector, Infantry, Anti Tank (PIAT) was a British anti-tank weapon developed during the Second World War. The PIAT was designed in response to the British Army's need for a more effective hand-held infantry anti-tank weapon. It consisted of a steel tube, a trigger mechanism and firing spring, and was based on the spigot mortar system; instead of using a propellant to directly fire a round, the spring was cocked and tightened. When the trigger was pulled, it released the spring which pushed the spigot forward into the rear of the bomb. This detonated the propellant in the bomb itself, which was then thrown forward off the spigot. It possessed an effective range of approximately 100 yards (90 m).