Direct Proof Of Use
The clearest public evidence for the MT-12 100 mm ammunition suite in the 2014 Russia-Ukraine War is a July 2022 Defense Express report on Ukrainian Ministry of Defense footage from the 93rd Mechanized Brigade. The article states that the unit was using a 100 mm MT-12 Rapira anti-tank gun and that Ukraine Weapons Tracker identified Bulgarian-made 100 mm 3UBK2 HEAT-FRAG projectiles, manufactured in 1987, being loaded into the gun.
Oryx's inventory of Bulgarian military support to Ukraine separately lists 100 mm 3UBK2 HEAT-FRAG anti-tank rounds as documented before July 2022. That inventory supports the transfer and fielding trail for the specific round type, while the Defense Express report ties the rounds to Ukrainian MT-12 loading footage in combat-service context.
Sources: Defense Express Bulgarian MT-12 Shells, Oryx Bulgaria Arms Ukraine
Timeline
By late July 2022, public evidence showed Ukrainian crews using the MT-12 Rapira and loading 100 mm 3UBK2 rounds. RFE/RL published front-line reporting from artillerymen of Ukraine's 93rd Mechanized Brigade in Kharkiv region on July 28, 2022, documenting the same unit operating Rapira anti-tank guns against Russian forces.
The available open sources do not prove a full inventory size, total expenditure, or every 100 mm round variant used in Ukraine. They do support a narrower statement: Ukrainian forces fielded at least Bulgarian-made 3UBK2 HEAT-FRAG rounds from the MT-12/T-12 ammunition family with MT-12 Rapira guns during the full-scale phase of the war.
Sources: Defense Express Bulgarian MT-12 Shells, Oryx Bulgaria Arms Ukraine, RFE/RL Kharkiv Rapira
Operational Context
The ammunition evidence sits inside Ukraine's continued use of Soviet-standard 100 mm MT-12 Rapira guns. Defense Express reported that Rapira guns were being used by the 93rd Mechanized Brigade, Ukrainian marines, and the National Guard, and linked that use to a need for continuing imports of 100 mm shells. The documented 3UBK2 examples were therefore not a standalone weapon system in the theater; they were ammunition for an existing towed anti-tank gun fleet.
For this page, possession and transfer are separated from use. Oryx supports the presence of Bulgarian 3UBK2 HEAT-FRAG rounds in the Ukraine support stream before July 2022. Defense Express provides the direct battlefield-use connection by reporting those rounds loaded by Ukrainian troops into an MT-12 Rapira in 93rd Mechanized Brigade footage. RFE/RL adds independent unit and theater context for 93rd Brigade Rapira operations in the Kharkiv region, but it does not identify the ammunition type.
Sources: Defense Express Bulgarian MT-12 Shells, Oryx Bulgaria Arms Ukraine, RFE/RL Kharkiv Rapira
