Soviet 3BK-21B HEAT-FS Projectile for 125mm 3VBK-17 round
The 3BK-21B High Explosive Anti-Tank Fin Stabilised (HEAT-FS) projectile is part of a round designed for Soviet and Russian tanks. As with all 125mm ammunition in this family, it is comprised of two parts - a projectile assembly and separate charge. This ammunition can be fired from T-90, T-80, T-72, T-64 and T-62 tanks with a 125mm gun.
It is important to note that in this case the name of the complete round - 3VBK-17 - appears to be used for two different projectile assemblies, the 3BK-21 with a copper liner, and the 3BK-21B with a DU liner. For this reason, it should not be assumed that every 3VBK-17 round contains DU. Earlier rounds, such as the 3BK-18 (pictured), were made with steel liners
Unlike most other DU weapons, the 3BK-21B is not a kinetic energy penetrator. HEAT rounds utilise a shaped explosive charge which detonates very close to the target. The cone shape in the charge concentrates the explosion, and the metal lining the cone is heated up to a state of superplasticity and forms into a jet of metal, moving at an extremely fast speed, which then punches through armour.
The earlier projectiles for this type of ammunition had a steel lining. The 3BK-21 was first produced in 1980, and the 3BK-21B in 1982. The former apparently performed better against rolled homogeneous armour, whereas the 3BK-21B apparently performed better against complex advanced armour materials. It is not clear what material properties of DU have informed the choice of material.
Subsequent 125mm HEAT-FS rounds have been produced for this range of tanks, but no information is available about the material used in the liner. These include the 3VBK-21, 3VBK-25 and 3VBK-27. One innovation in the later rounds is the inclusion of multiple charges to defeat explosive reactive armour. It is not known whether this change meant that DU was no longer a suitable material for this type of munition.
Because of the uncertainties surrounding the composition of these later rounds, and whether they have superseded the 3VBK-17 with a 3BK-21B projectile, it is not clear whether current Russian HEAT-FS ammunition is likely to contain DU.
ICBUW is not aware of any evidence that DU ammunition has been exported to the countries which field Russian or Soviet-made tanks. However it seems likely that the armed forces of ex-Soviet states are still equipped with Soviet era ammunition for tank forces, which may include DU rounds.