Serbia Presents Heavy 203 mm TSMB Mortar

Serbia has officially presented the heavy 203 mm self-propelled mortar TSMB, designed to defeat bunkers and other fortifications.

Army Recognition reported on the system’s capabilities at the Partner 2025 exhibition in Belgrade.

The heavy mortar was developed from a modified M-65 howitzer, re-barrelled to an elongated 203 mm calibre. The unusual solution, combined with a wheeled chassis, is designed to provide the system with the mobility to engage fortified positions, bunkers, and entrenched targets.

It is stated that the system can fire up to three rounds per minute, launching 100 kg projectiles to ranges of 6-12.5 km. An onboard ballistic computer and inertial system are said to provide firing accuracy.

The system offers an azimuth traverse of ±23.5°, enabling the weapon to shift fire without requiring relocation. With a maximum road speed of 80 km/h and an operational range of up to 600 km, the TSMB is intended to employ shoot-and-scoot tactics.

The vehicle is crewed by four people: driver, commander, gunner, and assistant gunner. An integrated automatic loader simplifies the gunner and assistant gunner’s tasks.

Photos indicate the mortar is breech-loading — fired through the breech like a conventional howitzer — although rounds can also be loaded muzzle-first in a more traditional mortar style.

A 203 mm mortar calibre is uncommon, so Serbian developers say they created a complete munition-system package. Belgrade’s Military Technical Institute has developed a line of 203 mm mortar ammunition for the program.

According to the institute’s documentation, a standard 100 kg shell contains 27 kg of an unspecified plastic explosive and can reach a maximum range of 12 km, with a muzzle velocity of approximately 400 m/s.

Exhibitors at Partner 2025 stated that the projectile creates a continuous damage zone of approximately 75 m on impact, allowing for the saturation of designated areas.

Planned munitions include cluster, thermobaric, and active-reactive (rocket-assisted) rounds to extend range. Developers also noted potential integration with modular precision fuzing systems for urban or mountain operations.

The 19-ton system is mounted on a FAP 6×6 wheeled chassis with an armoured cab, aiming to balance survivability and mobility.