The M77 Oganj (fire) multiple launch rocket system was developed in Yugoslavia in the late 1960s. Its prototype was first publicly revealed in 1975 and production commenced in 1980s. This artillery system saw action during the Yugoslav wars. Currently Serbian Army operates about 70 of these systems. A small number might also be in service with other former-Yugoslavia countries.

   The M77 Oganj has 32 launching tubes for 128-mm rockets. It fires warheads with anti-tank or anti-personnel submunitions. Maximum range of fire is 20.6 km. A full salvo of this rocket system covers area of 0.36 - 1.1 ha, depending on the warhead. It can also fire Serbian newly developed Grad-M and Grad-2000 rockets with improved range and firepower.

   The M77 Oganj MLRS is mounted on the FAP 2026 6x6 truck. A 12.7-mm machine gun is mounted on top of the roof for self-defense. Vehicle is fitted with a central tyre inflation system.

   Vehicle carries a full set of reload rockets, stored behind the cab in the automatic loader. It speeds up reloading process, however this rocket system can also be reloaded manually. The M77 Oganj can launch two sets of rockets from traveling and leave firing position within 6.5 minutes. In traveling position rocket launcher is covered by hydraulically operated canvas cover, which makes it hard to recognize, as vehicle looks like an ordinary utility truck.

Variants

   Oganj 2000 ER, a recently developed 122-mm rocket system, based on the Russian KamAZ 8x8 truck. It has 50 launching tubes and carries another 50 reload rockets.