The AO-2.5RT is an incendiary cluster munition that is prohibited by the Convention on Cluster Munitions. 2 Although use for smoke screens may be legal in specific circumstances, visual evidence of an AO-2.5RT in the Syrian conflict is highly correlated to illegal usage.
The AO-2.5RT bomb consists of two hemispheres connected with each other by an igniter and a ring of five blades. Shoulders increase the spread and cause the bomb to be unprotected. At the moment of hitting the ground, the bomb splits into two parts, which are thrown to a height of 1.2-1.5 m, and then explode." 1
The AO-2.5RT, and the AO-2.5RTM variation, are both spin stabilized centrifugally armed incendiary submunitions released from either the RBK-500 cluster bomb or a BKF cassette from a KMGU dispenser. An RBK-500 cargo munition payload contains 108 AO-2.5RT submunitions. The BKF cassette contains 12 submunitions, with 96 bomblets in a full KMGU dispenser.
The AO-25RT submunition is made from cast steel and is pre-fragmented to increase projectile spread upon detonation. On hard concrete the submunition halves will usually produce a fragmentation pattern indicating a relatively even spread in all directions.
The detonator fuze arms by means of centrifugal force or the absence or reduction of centripetal force. The fuze has been identified as an i-352V or a 9E246M. On release from the RBK-500 or BKF cassette the submunition spins in the correct orientation by means of the arming vanes. The weights in the pantograph fuze are forced outwards leaving two small creep springs as the only holding device once armed. These are overcome on impact. The pin impacts the primer initiating a black powder charge that separates the two halves of the submunition. After a pyrotechnic delay of up to 1.5 seconds the detonators of the two respective halves are initiated and the two main charges explode.
Most AO-2.5RTs used today originate from the former Soviet Union. Moldova, Macedonia, Peru and Slovakia are believed to have destroyed their stockpiles of this weapon.
The AO-2.5RT and AO-2.5RTM vary slightly in their appearance. The AO-2.5RT center band is not flush while the AO-2.5RTM band is flush with the cylindrical shape.
The body of the AO-25RT is painted silver with other identification markings in black Cyrillic. Typically the designation, AO-2,5RT, and the explosive fill TG-40, along with the usual factory number and year of manufacture will be included.