EDEX 2025: Slovakia's MSM Land Systems presents upgraded ZSU-23-4 SVK anti-aircraft gun.

MSM Land Systems rolled out the ZSU-23-4 SVK at EDEX 2025, a modernization of the Soviet-era ZSU-23-4 Shilka self-propelled anti-aircraft gun.

At EDEX 2025, the Slovakian company MSM Land Systems presented the ZSU-23-4 SVK, a modernized Shilka self-propelled anti-aircraft gun (SPAAG), as part of its broader portfolio covering repairs, modernization, and upgrades of tracked and wheeled military vehicles. The upgrade is intended to preserve the functional relevance of a military asset originally developed in the Soviet Union and still held in the inventories of numerous armed forces. The presentation positioned the ZSU-23-4 SVK within a complete industrial framework maintained by the company, signaling that existing operators of Shilka variants can rely on this modernization path to extend their operational service life.
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The ZSU-23-4 SVK Shilka retains most of the original ZSU-23-4 characteristics, such as its quad 23 mm cannon turret and the GM-575 tracked chassis, but seems to incorporate a missile launcher box on the top of the turret. (Picture source: Army Recognition)

MSM Land Systems is a Slovakian enterprise specializing in overhauling military tracked and wheeled vehicles, manufacturing special ISO 1C containers and vehicle superstructures, as well as maintaining NATO-compatible bridge layers and artillery systems for armed forces, police, fire, and rescue services. For instance, MSM supports and modernizes, for the Slovak Armed Forces, the BVP Šakal infantry fighting vehicle, the T-72 Scarab main battle tank, the BM-21MU and RM-70 Vampire multiple rocket launchers, the DANA M2 and DITA self-propelled howitzers, and engineering vehicles like the AM-50EX and AM-70EX bridge layers. In addition, it offers vehicles such as the Aligator Master II 4x4 and Patriot armored vehicles, as well as DECON decontamination vehicles. MSM Land Systems also serves as an authorized dealer and service center for Tatra Trucks, and belongs to the Czechoslovak Group, a multi-division industrial cluster active in defense, ammunition, mobility, aerospace, and other sectors, with about 400 employees and an annual turnover of about €48 million.

The ZSU-23-4 SVK Shilka presented by MSM Land Systems retains most of the original ZSU-23-4 characteristics, such as its quad 23 mm cannon turret and the GM-575 tracked chassis, but seems to incorporate a missile launcher box on the top of the turret. The ZSU-23-4 SVK measures 6,54 meters in length, 3,13 meters in width, and reaches a height of 3,7 meters when the radar is raised, with a combat weight between 20 and 22 tons depending on the user's requirements. The standard crew configuration consists of four members, including driver, gunner, loader, and commander, although a three-person layout is available when a combined gunner-loader arrangement is requested. The SVK maintains a maximum speed of approximately 50 km/h, providing sufficient mobility to move with mechanized and armored units in varied terrain. The modernization allows countries to continue to assign operational tasks to their Shilka systems, which have offered, since the 1960s, a low-altitude air defense coverage for moving columns.

The armament configuration relies on the AZP-23 mount fitted with four 23 mm 2A7M cannons firing 23×152B ammunition, with a total ammunition capacity of 2,000 rounds distributed between the upper and lower cannons. The 2A7M could fire multiple ammunition types, including armor-piercing incendiary tracer (BZT), high explosive incendiary (OFZ), and high explosive incendiary tracer (OFZT), allowing operators to tailor belts to air defense or ground support tasks. The elevation range extends from minus 4 degrees to plus 85 degrees, enabling engagement of aircraft, rotary-wing targets, elevated firing positions, and urban structures. Each cannon has a high cyclic rate of fire, and the water-cooled barrels allow sustained bursts, compared to earlier variants that experienced barrel overheating and runaway gun issues, prior to later mechanical improvements. While practical firing performance remains limited by heating cycles, ammunition consumption, and the mechanical structure of the turret, the density of fire remains the defining characteristic of the Shilka.

The established GM-575 chassis incorporates here a 280 hp V-6R diesel engine based on the 20-liter V-2 engine lineage that powered many Soviet armored vehicles. This engine is coupled to a manual transmission with five forward gears and one reverse, with power transmitted through planetary steering mechanisms and final drives to the tracked running gear. The chassis also includes a torsion bar suspension system with hydraulic shock absorbers on selected road wheels, enabling the vehicle to negotiate 0,7 meter vertical obstacles, 2,5 meter trenches, 1 meter of fording depth, and gradients of 30 degrees. The Shilka has an operational range of about 450 km on roads and 300 km cross-country, while its fuel tanks total approximately 521 liters. The vehicle includes an NBC filtration system, internal and external communications, a gas turbine generator DG4M-1 for onboard power, infrared driving devices, a TNA-2 navigation system, and an internal layout divided between the driving compartment, the fighting compartment, and the engine compartment.

The fire control system of the ZSU-23-4 is built around the same design that has defined the Shilka family since its introduction in the 1960s, historically employing the RPK-2 Tobol radar mounted on collapsible supports at the rear of the turret. This radar offers detection capabilities up to approximately 20 km and can track aircraft for short-range engagements despite ground clutter challenges below about 60 meters altitude. The turret is fully stabilized, allowing firing on the move, and an electromechanical fire solution calculator uses radar input and gyroscopic orientation data to compute azimuth and elevation lead angles for each burst. Limitations known from earlier models, including the need for periodic radar resets, tracking difficulties at high angular speeds, and cooling requirements for the guns, have been addressed over decades through multiple modernization paths in various countries. The ZSU-23-4 SVK could maintain the original radar layout while enabling customers to incorporate more modern optical devices, updated rangefinding solutions, or other mission-specific subsystems.

The ZSU-23-4 was developed between 1957 and 1960, its production started in 1964, and it continues to be used until today through multiple national upgrade programs. More than 6,500 units of the original Soviet Shilka were built, and many remain in service or storage around the world. Throughout decades of use, the SPAAG has been fielded in conflicts including the Yom Kippur War, the War of Attrition, the Vietnam War, the Soviet Afghan War, the Iran-Iraq War, the Gulf War, the Chechen conflicts, the Syrian Civil War, and the Russo-Ukrainian War. Variants produced in Russia, Belarus, Ukraine, Poland, Vietnam, Iran, India, and the Netherlands introduced missile launchers, passive optical tracking, digital fire control, hydrostatic transmissions, updated radars, laser rangefinders, and increased ammunition capacities. These continuous modernization efforts illustrate that the underlying architecture remains adaptable and that many operators continue to retain the Shilka, as a complement to more modern missile-based air defense systems.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.