Tracked fire support vehicles: A return to ‘light tanks’?

Attaching armoured fire support vehicles to light infantry units can enhance survival and support offensive operations. While such vehicles have been offered in various configurations for many years, recently there appears to be increased interest in acquiring such vehicles.

Several factors differentiate fire support vehicles (FSVs), whether wheeled or tracked, from other armoured fighting vehicles. FSVs are often based on existing wheeled (typically 6×6 or 8×8) or tracked armoured personnel carrier (APC) or infantry fighting vehicle (IFV) platform families, which are modified with a turret armed with a large-calibre gun. Consequently, more lightly-armoured and therefore lighter than a main battle tank (MBT), a fact which has often led to them being referred to as ‘light tanks’. However, the ‘tank’ label can be somewhat misleading, as these vehicles lack sufficient protection to take on the doctrinal role of a ‘true’ tank in conducting breakthroughs or combating heavily-armoured targets. Despite often being based on a common platform to APCs or IFVs, typically FSVs lack the capability to carry a squad of mounted infantry. Historically their main armament has often tended to be lower-calibre than that of a modern MBT, but this trend has shifted in recent years, as low-recoil versions of 120 mm and 125 mm armaments have become adopted on lighter vehicles.

These characteristics reflect the FSV’s primary mission, which is to provide infantry units with direct fire support (as opposed to indirect fire support via artillery). This requires the ability to deploy globally with light/medium-weight forces and to keep pace with them over difficult terrain. As a rule, FSVs are not expected to directly engage heavily-armoured combatants such as MBTs, although their primary armament may be capable of doing so, and they can be armed with turret-mounted anti-tank guided missiles (ATGMs) to augment their anti-armour capabilities.

Overall, FSVs can be considered medium-weight vehicles, primarily intended to engage stationary fortifications such as bunkers, infantry, as well as light and medium-weight vehicles. While FSVs are generally tasked with supporting light forces, they can also be attached to mechanised infantry units, freeing up MBTs for other missions.

M10 Booker

The US Army is currently working toward fielding the new M10 Booker FSV, procured under the Mobile Protected Firepower (MPF) programme. As defined by the Pentagon, the M10 is primarily intended for providing fire support to US Army Infantry Brigade Combat Teams (IBCTs), enhancing their overall effectiveness.

The M10 Booker is produced by General Dynamics Land Systems (GDLS) and is based on a heavily-modified version of the ASCOD 2 (Austrian-Spanish Cooperative Development) platform. The M10 hull has been substantially modified from the original, but retains a front-mounted powerpack, comprising an MTU 8V 199 TE21 diesel engine developing 600 kW (805 hp), coupled to an Allison 3040 MX six-speed (four forward and two reverse gears) automatic transmission. The platform is equipped with hydro-pneumatic suspension in each road arm, using less interior volume than the torsion bars typically used on the ASCOD family, while the tracks are the T161 model, as used on the M2/M3 Bradley IFV. The vehicle lacks an auxiliary power unit (APU), but is fitted with 6T Li-ion batteries, which provide it with a silent watch capability, allowing it to run core systems with the engine switched off.

In terms of armament, the vehicle is armed with the XM35 105 mm L52 rifled main gun, a coaxial 7.62 mm machine gun (MG), and a 12.7 mm heavy machine gun (HMG) in a ring-mount at the commander’s hatch. The gunner is provided with a day and thermal sight on the top-right hand side of the turret, while the commander is provided with an independent panoramic day and thermal sight on the top-left hand side of the turret. Additionally, the crew are provided with a suite of cameras to provide 360° local situational awareness around the vehicle.

In terms of dimensions, the M10 Booker is actually slightly taller than the M1 Abrams MBT, but has a slightly lower width and length. The turret shares some commonality to that of the M1 Abrams in terms of line-replaceable parts, along with crew layout, and Army sources have stated that the fire control system (FCS) is similar to that of Abrams. At 38 tonnes, the M10’s vehicle weight is approximately half that of the Abrams. The M10 is too large to be transported by C-130, but two vehicles will fit inside a C-17; by contrast, only one Abrams can be transported per C-17. Importantly, the M10 can cross bridges too weak for the Abrams, enabling the Army to project mobile force protection in areas not accessible by MBTs.

The M10’s characteristics have led some observers to refer to it as a light tank, but the Pentagon spoke out against this characterisation. The primary objection to the light tank label is found in the vehicle’s mission statement, which is to provide direct fire to neutralise obstacles typically faced by infantry, such as bunkers, gun emplacements or light armoured vehicles. “MPF is not designed to be able to engage enemy tanks,” noted Ashley John, a spokeswoman for the Army’s Program Executive Office Ground Systems, in 2022. Maj Gen Glenn Dean, Program Executive Officer for Ground Combat Systems, separately stressed that “light tanks” historically have performed reconnaissance functions, “and this is not a reconnaissance vehicle, it’s an assault gun”.

GDLS was awarded the low-rate initial production (LRIP) contract in June 2022. That contract covered 96 vehicles, the first of which was delivered to the Army in April 2024. In August 2024, the Army awarded the firm a second LRIP contract over an unspecified number of vehicles. The Army’s acquisition objective is 504 units, although officials caution that this figure could be revised. Each infantry division is to be assigned one battalion of 42 M10s, enough to provide each IBCT a company with 14 vehicles. Current planning calls for the first unit equipped (FUE) status to be achieved in the fourth quarter of Fiscal Year (FY) 2025. The first company is expected to be assigned to the 82nd Airborne Division at Fort Liberty, North Carolina. The Army has not stated whether that unit will be the first to receive a complete battalion, or whether the remaining companies of the first battalion set would be assigned to different divisions.

In July 2024, airborne soldiers at Fort Liberty began an intense new equipment training and test cycle on LRIP vehicles. The results of the testing, which was expected to run for three months, were not published before this issue went to press. The last known planning called for initiating the initial operational test & evaluation (IOT&E) in January 2025 if the results at Fort Liberty were positive. The IOT&E event will identify any changes GDLS needs to make to the system. A positive IOT&E report would open the path to a full-rate production (FRP) decision in the third quarter of FY 2025.

Sabrah light tank

The M10 Booker is not the only FSV based on GDELS’ ASCOD 2 design. Israel’s Elbit Systems offers the Sabrah FSV in both a tracked variant based on the ASCOD 2 and a wheeled variant based on the Pandur 2 8×8. Both feature an Elbit two-person turret and the 105LW rifled, low recoil 105 mm gun. The stabilised turret also mounts an FN MAG 7.62 mm MG and eight smoke grenade launchers. The tank carries 12 ready rounds in the autoloader, plus an additional 24 in the hull. A pod of two ATGMs is offered as an option, as is the Iron Fist Active protection system.

The Sabrah modification was offered in 2020 to meet a requirement of the Philippines Army for a ‘light tank’. Manila placed an order for 18 tracked and 10 wheeled Sabrah FSVs in January 2021. The first nine of the tracked version formally entered service in March 2024. Elbit has stated that the approximately 30-33 tonne vehicle features a range of the firm’s subsystems, including optronic sights, a digital fire control system, TORCH-XTM battle management system, E-LynXTM software defined radio system, and life-support systems.

Kaplan MT

Türkiye’s FNSS Kaplan MT is another notable in-service tracked FSV. The base vehicle is derived from FNSS’ Kaplan family, using paired with a John Cockerill Defence 3105 two-person turret, armed with the Cockerill 105HP (high pressure) 105 mm L51 rifled gun, coupled to an autoloader with 12 ready rounds. Secondary armament includes a coaxial 7.62 mm MG, and a roof-mounted 7.62 MG or 12.7 mm HMG for the vehicle commander, which can be either pintle-mounted or a integrated into a remote weapon station (RWS). According to PT Pinded, the vehicle combat weight can range from 30-35 tonnes. FNSS have also offered the vehicle with the Pulat hard-kill active protection system (APS), which is a Turkish derivative of Ukraine’s Microtek Zaslon APS design.

Indonesia was the first user of the Kaplan MT, which is known as the Harimau in Indonesian service, and is produced jointly by Türkiye’s FNSS and Indonesia’s PT Pindad. Production began in 2017, and the first batch of 10 vehicles was handed over to Indonesia’s armed forces in March 2024, and the initial order for 18 vehicles was reported to have been completed by October 2024. Brazil has also been considering the Kaplan MT (as well as the Sabrah, CV90120, and Lynx 120) as part of the Armoured Combat Vehicles (VBC CC) component of its Army Armoured Forces Strategic Programme (Prg EE F Bld). Previously, in November 2022, Brazil had selected the Centauro II 8×8 wheeled FSV for its ‘Viatura Blindada de Combate de Cavalria – Média Sobra Rodas’ (VBC Cav – MSR 8×8) programme.

CV90120

Since the 1990s, BAE Systems Hägglunds has developed several variants of the CV90 AFV which were equipped with larger calibre weapons, including the CV90105 and CV90120. The most recent offer in this category is the CV90120MkIV, based on the manufacturer’s latest CV90MkIV platform, fitted with a two-person turret and armed with a 120 mm smoothbore gun. It is intended to provide direct fire support, and has previously been advertised by BAE as also providing a “sustained long-range anti-tank capability”. While the armament would certainly mean the latter is possible, the fact that the vehicle’s armour is considerably weaker than that of a typical MBT leaves it more vulnerable to return fire than an MBT in the anti-tank role.

BAE Systems have offered a version of the CV90120 for some years, even prior to their latest version based on MkIV. Originally, their 120 mm armament offering was based on the Ruag CTG 120/L50 (CTG = Compact Tank Gun) 120 mm gun, however following Ruag ceasing to offer this weapon, the primary armament was changed to the Rheinmetall Rh 120 LLR L/47 (LLR = Light, Low-Recoil) gun. The 120 mm gun accommodates all NATO standard 120 mm tank munitions as well as gun-launched anti-tank guided missiles (GLATGMs) and is provided with an autoloader. BAE Systems have previously advertised a maximum rate of fire of 12-14 rds/min. Secondary armament comprises a 7.62 mm coaxial MG, and additional armaments including a 7.62 mm MG or 12.7 mm HMG, or 40 mm automatic grenade launcher (AGL) can be mounted in a RWS on the turret roof.

The vehicle is also optionally offered with soft-and hard-kill APSs. The former can include laser, radar, and missile warning receivers, coupled to smoke grenade launchers, while the latter is understood to include various user-defined hard-kill APSs.

Lynx 120

Rheinmetall Defence presented the Lynx 120 FSV in February 2022. This version featured what appeared to be the two-person turret used on the KF51 Panther MBT, armed with a Rheinmetall Rh140 L/44 gun, and mated to the KF41 Lynx tracked platform. According to Rheinmetall’s accompanying press release, the Lynx 120’s gun was compatible with Rheinmetall’s DM11 three-mode programmable HE-munition. This enables the Lynx 120 to engage targets ranging from bunkers (point detonation) to light- medium-armoured vehicles (delayed point detonation) to personnel in the open (air burst). In addition to DM11, the 120 mm is compatible with NATO 120 mm ammunition natures, including high-explosive anti-tank (HEAT) and armour-piercing fin-stabilised discarding sabot (APFSDS) rounds, enabling destruction of heavily-armoured targets such as MBTs. Secondary armament includes a coaxial 12.7 mm HMG, and a 7.62 mm MG mounted in a Natter RWS on the turret. A 360° camera system with automatic target detection and tracking assists the crew with situational awareness.

At Eurosatory 2024, Rheinmetall showed a further development of their Lynx-based FSV concept, under the name ‘Lynx 120mm’. This version differed slightly from the original Lynx 120 shown in 2022, using a smaller and lighter Leonardo Hitfact II turret mated to the KF41 Lynx hull, and armed with the Leonardo 120/45 gun. The turret is offered as a 2-person turret with autoloader or 3-person turret, and the Leonardo 105/52 gun can be selected as a lower-calibre alternative to the 120/45 gun.

Rheinmetall underscores the simplified vehicle architecture and plug-and-play design which will facilitate future upgrades. Modularity is also displayed by the vehicle’s defensive suite, which includes scalable passive armour packages, and Rheinmetall’s Strikeshield hard-kill APS as options.

An FSV Renaissance?

As the tactical environment continues to evolve, there appears to be a resurgence of interest in FSVs, both wheeled and tracked. Ongoing conflicts, especially in Ukraine, have demonstrated that heavy armour is often inadequate protection against new anti-armour threats such as drones and loitering munitions. Yet at the same time, there remains demand for large-calibre direct fire capabilities to support infantry or light- and medium-weight forces. Here, tracked FSVs provide a number of important advantages over traditional MBTs.

FSVs have notably lower acquisition, maintenance, and running costs than MBTs, and their adoption also allows armed forces an opportunity to increase parts commonality and reduce the logistical burden across their fleet, if their chosen FSV uses the same base platform family as already in-service IFVs or APCs. To armed forces with limited budgets, tracked FSVs offer a means to build capable armoured formations at a significantly lower cost than the – often prohibitive – acquisition of modern MBTs. Additionally, FSVs’ lighter weight provides a multitude of other advantages, including reduced fuel consumption, easier recovery, the ability to traverse bridges and gaps inaccessible to MBTs, as well as being easier to transport by air. Such factors make them an attractive prospect in most tactical scenarios.

While FSVs are far more lightly armoured than MBTs, their survivability can nonetheless reach a respectable level though adoption of more ‘left of boom’ approaches, such as hard- and soft-kill APSs, signature reduction, and (relatively) lightweight add-ons such as bar armour and overhead protection cages. Over time, they are also likely to be enhanced with onboard reconnaissance UAVs or loitering munitions to detect and neutralise threats at beyond-line-of-sight ranges, or network with unmanned ground vehicles (UGVs). Depending on the operational scenario, these technologies could at least partially reduce the survivability gap between FSVs and MBTs. Throughout history, armies have fielded balanced forces consisting of complementary light, medium and heavy forces. The validity of this approach still resonates today.

Sidney E. Dean