With the emergence of the NATO alliance following the end of World War 2 (1939-1945) there came a decided move to standardization of various weapon systems, components and logistics. This, in turn, saw the rise of standardized small arms and artillery calibers which, in the latter, this became the 155mm projectile. This caliber was selected by NATO authorities against "Basic Military Requirement 39" back in 1963 for its strong balance of range-to-firepower and designs like the FH70 took hold for operators in Europe and across the globe.
NATO's BMR39 initiative called for a weapon system able to reach firing ranges of 24 kilometers - additionally rocket-assisted projectiles would increase this to a range of 30 kilometers as needed. An Auxiliary Power unit, or APU, would be integrated into the carriage system to allow the firing crew to move their artillery piece across short distances without needing the direct services of a mover vehicle. Burst sustainability called for up to three rounds within a twenty-second window and up to six rounds in under a minute. Standard sustained fire would require about two rounds-per-minute.
Up to this point, a majority of European powers still relied on the tried-and-true M114 of 155mm caliber. This howitzer was of American origin and proved itself wholeheartedly in the fighting of World War 2. However, introduced in 1942, the design saw its best fighting days behind it and the new battlefield required an equally-new modern artillery piece - lightweight, streamlined and just as effective. Despite its age, the M114 nevertheless went on to have an exceptional, extended service life as it saw fighting into the middle part of the 1990s. Another candidate for replacement by the FH70 would become the British BL 5.5" gun. This was another weapon of World War 2, produced in the thousands, that managed to see fighting into the 1980s.
The FH70 ultimately became a joint-development of Britain's Vickers Limited and Royal Armament Research and Development Establishment (RARDE) as well as West Germany's Rheinmetall. Work began in 1968 and, in 1970, evolved to include input from Italy. To go along with the new gun tube and carriage being fashioned would be various ammunition types covering High-Explosive (HE), illuminating and smoke generators.
The resulting weapon was of a largely conventional design arrangement with the gun tube sat over the mounting hardware and the mounting component installed over a "split-trail" carriage featuring two roadwheels. The trail arms worked as both a tow arm for road transportation and as the support arms for when the weapon was made ready to fire. The gun tube was given a large, twin-baffled muzzle brake at its "business end" and the recoil mechanism was fitted under the barrel in the usual way. Elevation and traversal controls were all included as was the required (removable) APU unit. A vertical-sliding breech mechanism provided the gunnery crew with quick, effective access to the all-important firing chamber.
Overall weight of what became the "FH70" was over 17,000lb. The barrel alone measured 19.7 feet long and the carriage had a 7.2 foot width. The typical operating crew was eight, each charged with a particular function of the weapon for maximum efficiency. The mounting hardware allowed for an elevation span of -5 to +70 degrees, giving the weapon a good deal of tactical flexibility, and the traversal was limited to 56 degrees either side from centerline.
In practice, the gun gave seemingly good field performance with a burst rate-of-fire of three rounds per every fifteen seconds. Sustained fire could reach up to six rounds-per-minute. Muzzle velocity of the outgoing shell was 2,713 feet-per-second and range was out to the required 24 kilometers (30 km with rocket-assist). However, early service did reveal some issues with the feed mechanism prone to dust collection, inconsistent APU performance and construction of key operating parts. Some remedies were enacted into the latter part of the 1980s while others simply forced a rewriting of operating procedures for gunnery crews.
The FH70 was formally adopted for service in 1980 with European operators becoming Britain, Estonia, Italy, Netherlands, Norway and West Germany. The largest operator of these was West Germany with 150 pieces purchased followed by 67 units operated by the British military. Netherlands, Norway, West Germany (Germany) and Britain have all since become former operators of the system (2018).
Overseas users were Japan, Lebanon, Malaysia, Morocco, Oman and Saudi Arabia. Japan took to local license production of the gun through Japan Steel Works and 480 were built in this fashion. Italy has managed a stock of some 182 units and Saudi Arabia procured 72 of their own.
So while there is continued global use of the FH70, its days as a frontline system, at least by Western standards, appear to be numbered as several of the primary project contributors have given up use of the product (typically artillery pieces see decades-upon-decades of consistent service with even large militaries). Nevertheless, for some countries, the weapon continues to give good service on the modern, digitally-driven battlefield.