In order to "up-gun" its available tank-killing inventory to better face increased armor thickness of German tanks during World War 2 (1939-1945), the British Army modified their existing "Valentine" Infantry Tanks (detailed elsewhere on this site) to mount the more lethal 76.2mm gun (also known as the "17-pounder"). The "Archer", as the converted model came to be known, was unique in that it fitted the main gun in a fixed superstructure designed to fire over the rear-set engine compartment. As such, the vehicle could be set at key strategic positions and utilized moreso as an assault tank laying in wait to ambush enemy targets. With the driver and front of the vehicle already pointed away from the action, the Archer crew could fire the gun and quickly relocate to a new, favorable position to repeat the action. Couple this "guerrilla-style" hit-and-run tactic with the vehicle's naturally low profile and the Archer would find success on the battlefield throughout the latter half of World War 2 serving the British Royal Artillery regiment.
In the early phases of the war, British authorities were somewhat keen on the need to upgrade their anti-armor capabilities, though this need perhaps less so than their German counterparts across the North Sea. The Germans were quick to utilized aging, less capable tracked chassis and reconstitute these still-serviceable forms for making stopgap tank-killing systems with hurried installations of ever more formidable armaments to these hulls. The British came to realize that their 57mm (6-pounder) anti-tank cannons would inevitably meet their matches on the modern battlefield and looked for a successor to mate with a self-propelled, tracked chassis. This proved quite unique to the British experience up to this point in the war for the 57mm armament was a relatively new addition to artillery inventory and the move to a new, unproven gun was something of a blind step forward. The new weapon system - 76.2mm in caliber and known as the "17-pounder" - was initially developed as a towed artillery piece. However, the weapon proved quite large and relatively heavy to be toted around with any level of quickness and the tracked hull designs that might have proved capable of mounting such a weapon were still some months away from becoming realistic possibilities. Therefore, the decision was made in the middle of 1942 to mount it on an existing tracked chassis as a stopgap solution all their own.
Initially, the idea proposed revolved around revamping the "Bishop" self-propelled gun to act as an anti-tank system. The Bishop herself mounted a powerful 25-pdr main gun but the revision would have seen her fit the newer 76.2mm system. This conversion idea fell to naught, as did another concerning the use of the Crusader tank which lacked the needed armor protection for crew and gun alike. Ultimately it was settled that the Valentine infantry tank would prove most suitable for the project. The Valentine was a proven commodity in British Army inventories and readily available in some number. As a whole, Valentine hull proved generally more readily adaptable of accepting a new armament mount as required for the 17-pdr. Interestingly, the Valentine was already considered a contender for a previous "up-gunning" project back in 1941 but, back then, it proved logistically easier to simply revise the Crusader tank turret for the task instead.
With the Valentine becoming the opportune candidate for the conversion process, work on the project steadily ramped up by early 1943. By March, a pair of pilot vehicles - one featuring a conventionally-set forward gun facing with the other fielding an unorthodox rear-facing gun mount - were made ready for evaluation. Through March and into April, these vehicles underwent a period of intense evaluation and authorities ultimately decreed that the rear-facing gun mount was in all actuality the best choice for the required need. This particular design sported a low profile making it a smaller target and the rear-facing gun held an inherent tactical advantage when firing at an alerted enemy while the vehicle itself was in retreat.
This prototype was selected for serial production and would feature much of the same components as the production Valentine tanks to help speed up their assembly - sans the turret of course, this replaced by a fixed, welded, open-topped superstructure (later models would incorporate a light armor covering). The new vehicle would include the same hull, gearbox and engine - the latter being a General Motors 6-cylinder diesel breed - as the Valentine it was born from. Additionally, the new mount was given a new gun sight system as well as a new engine cooling system while the guns traversal function was improved. The firm of Vickers-Armstrong was tabbed for production and handed a government contract for 800 vehicles to be built under the formal designation of "SP 17-pdr Valentine". Production was scheduled to commence in late 1943. The vehicle would eventually come to be known under the more recognizable name of "Archer" within its first few months of service.
The crew of the Archer would operate the gun actions from the superstructure position while exposed to the elements and battlefield dangers such as artillery and mortar fire. The driver remained in a covered position in the forward hull. The gun emplacement was seated at the front of the vehicle to help maintain balance. The main gun, when fired, would actually recoil backwards quite close to the driver's position in the hull and, as such, this required him to exist the vehicle whenever the firing action commenced. While fitted to the fixed superstructure, the main gun was traversable to a limited extent. The vehicle would be crewed by four personnel made up of the driver, commander, loader and gunner. A single 7.7mm Bren machine gun fitting was set up for self-defense against enemy infantry and low-flying enemy aircraft.
Once in service, British crews took some time to get accustomed to the strange arrangement that was the rear-facing gun. Conventional wisdom held that all armored vehicle armament faced forward toward the action with the driver set equally forward in the design - watching said action unfold along with the gunnery crew. However, once in practice, crews soon learned to play up on the strengths of their new Archers and the system went on to have a healthy battlefield existence. Members of the Royal Artillery companies were given the Archer and most ended up generally preferring them to its towed 17-pdr counterpart for obvious reasons.
With production numbers steadily growing, the Archer was officially fielded across the European Theater in October of 1944 where it ultimately saw actions across Northwest Europe and into the Allied landings of Italy. British artillery crews generally favored their Archers when compared to the American-made M10 Achilles tank destroyers they received via Lend-Lease. The standard operating tactic of the Archer was to sit in wait as an ambush weapon of sorts. The low profile generally made for a harder target to spot, allowing her to be hidden against earthen hills, in heavy woods and against structures. As the unsuspecting enemy approached within range of the 76.2mm main gun, the Archer crew would "light up" and fire off as many rounds as possible in a short window of opportunity, they maintaining the initiative of the moment. Before the enemy could respond with return fire, the Archer crew would displace or retreat to a position of improved advantage and perhaps repeat the process. The 17-pdr gun became a proven tank-killing system that could pierce the armor of just about every German vehicle then available, save for the heavier, thicker armored systems. Such an advantage in having the first-shot and, possible, the first-kill, provided the Archer system with a unique strategy that few other tank-killing systems of the war could match.
However, the Archer was not without her drawbacks - the fact that the driver had to stand outside of his vehicle so the gunnery crew could fire might add costly minutes to a quick getaway from enemy return fire. Also, her gun was limited in its traversal, essentially requiring the entire machine to be pointed in the direction of the enemy. With its open-topped superstructure, this also left the gunnery crew with little in the way of topside protection while the surrounding walls of light armor were quite thin and designed to deflect small arms fire and perhaps artillery spray.
These drawbacks eventually proved less than critical to Allied warplanners for the war in Europe had concluded by June of 1945 - Hitler committed suicide in late-April while the Germans officially capitulated in May. With production of the Archer still ongoing at war's end, the original contract for 800 examples was cancelled, leaving just 655 of the vehicles in current circulation. Such actions proved common practice worldwide where much of the costly wartime production was slashed or cancelled outright, leaving many projects in limbo if existing in any physical form at all. Regardless, the Archer had completed her storied tour in the most famous World War of them all. She went on to serve in her role with the British Army up until the middle of the 1950s before being retired in full.