With modern artillery a proven commodity on the battlefields of World War 1 (1914-1918), the concept of mobile artillery projecting systems evolved by the time of World War 2 (1939-1945). From this came an all-new generation of vehicles built upon the experience of the last great war and propelled a myriad of such designs into the Cold War decades. While the Americans and Soviets battled it out on their design boards, the British took on an indigenous Self-Propelled Artillery / Gun (SPA / SPG) design all their own as the FV433 "Abbot".
The FV433 utilized the chassis of the FV430 tracked vehicle family for logistical commonality. It retained the five-wheel running gear with a front-mounted drive sprocket and rear-mounted track idler. The engine was positioned to the left front of the hull, forcing the driver's position to the front right. Over the rear portion of the hull was fitted an all-new enclosed turret housing which managed the functions of the 105mm main gun.
As its categorization suggests, the FV433 was to serve in the "in-direct" fire support role, landing projectiles across an arc against target some nine miles away. In the event of all-out war against the Soviet Union in Europe, the FV433 would have had an important tactical role to play. The FV433 entered service in 1965 and became a part of the inventories of the British and Indian armies. The British retired their stock in 1995 while India has continued its use. Production of the vehicle was handled by the storied concern of Vickers and its formal designation (in the British Army) was "Gun Equipment 105mm L109 (Abbot)".
The vehicle featured a standard operating crew of six of which four were actually native to the vehicle itself and the other two trailing in the ammunition carrier. The primary crew was made up of the driver, the vehicle commander, the gunner and the loader. The loader also managed the onboard wireless set (radio). The ammunition crew was represented by a secondary commander and dedicated ammunition handler. The driver was the only one of the crew to reside in the hull proper - the other three positioned in the turret. The turret provided for a full 360-degree rotation with -5 / +70 degree elevation/depression and armed with the 105mm L13A1 main gun. The gun was capped by a double-baffle muzzle brake and featured a fume extractor along its midway point.
The L13A1 was afforded 40 projectiles of 105mm caliber with shells and cartridges loaded separately. Shells generally consisted of High-Explosive (HE) types though smoke, illumination, marking (red or orange coloring) and High-Explosive Squash Head (HESH) varieties were added. The HESH round was of particular note for it was designed to defeat fortified structures and could even be used to engage enemy armor. A well-trained, disciplined and experienced crew could reach a rate-of-fire of up to eight rounds per minute. Secondary armament (beyond any crew-carried personal weapons) included the 7.62mm L4A4 machine gun, this with 1,200 7.62mm NATO-standard rounds allocated. The L4A4 was a modernized form of the World War 2-era BREN light machine gun (0.303 British) featuring a chrome-plated steel barrel for prolonged firing. The vehicle also carried smoke grenade dischargers along the sides of the turret which allowed for a self-screening action when activated.
Power for the Abbot was served through a Rolls-Royce K60 Mk 4G multi-fueled opposed piston engine installation developing 240 horsepower at 3,750rpm. This provided the vehicle with a maximum road speed of 29 miles per hour and operational range of 300 miles (assuming ideal surfaces like roads). The hull was suspended atop a torsion bar suspension system which aided cross-country-travel and the vehicle was completed with a basic amphibious capability, propelled through water sources by the movement of its own tracks (up to 3 knots speed however). Following suit, the ammunition carrier was equally amphibious. Due to the persistent threat of nuclear weapons in the period, the Abbot crew was protected by an integral NBC (Nuclear, Biological, Chemical) system. Ballistics protection was achieved through 12mm armor plate thickness at critical facings.
In 1992, the British Army began accepting delivery of the all-modern AS-90 SPA system, thus bringing about a formal end to usage of the FV433 Abbot.