100 mm HEAT-FS BK-5M

total load of 34 ( T-54 ) or 43 ( T-55 ). The BK-5M has been referred to as the ZBK-5M, although the complete round designation is 3UBK-4. Tank units of the Russian Federation and Associated States (CIS) now use an improved version of this projectile known as the 3BK17M (see following entry). The BK-5M has also been produced in Bulgaria , China (Type 73), Czech Republic , Romania , Slovakia and Yugoslavia . In Bulgaria and Yugoslavia it was known as the HEAT-T M69 (probably no longer in production). Description The 100 mm HEAT-FS BK-5M is used with a fixed round, with the finned steel projectile rigidly secured to the brass cartridge case by a single shallow crimping ring. The base of the projectile, inside the cartridge case, is supported on a steel slip band seat while the projectile body is encircled by two copper drive bands set 21.6 mm apart. The front of the projectile has a conical ogive with the nose carrying a piezoelectric impact sensor connected internally to a VP-9 or GPV-2 super-quick base detonating fuze. When the fuze functions it ignites the explosive filling of 1.038 kg (nominal) of A-IX-1 (RDX/Wax). The filling is set behind a conical internal liner, to form a shaped charge producing a high-temperature particle jet capable of penetrating up to 380 mm of armour at any range. The base of the projectile carries an extension boom mounting six forward-folding steel fins. The fins snap out for flight stabilisation once the projectile has left the gun muzzle; when extended they have a diameter of 368.08 mm. The tailboom also contains a No 12 tracer element. The brass cartridge case (lacquered steel may also be used) contains approximately 4.65 kg of 18/1 Tr and 14/7 propellant in stick and powder form. A KW-13U percussion primer is threaded into the base. Brass cases are made of MK-75 brass and weigh 8.5 kg. The flange diameter is 147.5 mm. The 100 mm HEAT-FS BK-5M has a muzzle velocity of 900 m/s. Although it can penetrate up to 380 mm of armour set at 0º and 190 mm set at 60º, it has been calculated that the hit probability against a static tank sized target at 1,000 m is only 43 per cent. At 2,000 m the hit probability is reduced to a negligible 2 per cent. Maximum possible range is approximately 3,000 m. Authorised fuzes PIBD VP-9, GPV-2 or GPV-2R Equivalent rounds BULGARIA BULGARIA Manufacturer Kintex Type: Hollow charge UBK-4 Description: BK5 projectile length, fuzed, given as 460.6 mm and Hexogen explosive filling as 990 g. Propellant is 4.65 kg of MBL and cartridge case may be lacquered steel or brass. Muzzle velocity is 900 m/s Manufacturer Vazovski Machinostroitelni Zavodi Type: Hollow charge round Description: Understood to be HEAT-FS BK-5M. Armour penetration given as 300 mm. Fitted with PIBD GPV-2 fuze CHINA , PEOPLE'S REPUBLIC Manufacturer China North Industries (NORINCO) Type: HEAT-T Type 73 Description: Understood to be based on BK-5M but may be completely original design. Round weight 24 kg and length overall 1.071 m. Projectile weight 10.05 kg and length 587 mm. Muzzle velocity 1,000 m/s. Tracer burns for more than 2 seconds. Direct fire range 1,000 m CZECH REPUBLIC AND SLOVAKIA Manufacturer ZVS Dubnica Type: HEAT-FS PrSv Description: Projectile weighs 9.52 kg and contains 961 g of RDX/TNT. Uses cylindrical steel body with standoff nose spike and only four stabilising fins. Fin span, opened, is 257.8 mm. Steel cartridge case contains 4.47 kg of Dgtp propellant IRAN Manufacturer Defence Industries Organisation, Ammunition Group Type: HEAT Description: Appears to be an Iranian development with a modified 105 mm HEAT-T M456 series projectile allied to a 100 mm cartridge case. Total weight is 21.7 kg and explosive warhead weight is 1.2 kg; propellant weight is 5 kg. Muzzle velocity 1,000 m/s. Length overall 1.06 m. Fitted with PIBD M509A1 fuze. Offered for export sales ROMANIA Manufacturer SN ROMARM SA Type: HEAT-T BR-412R Description: Intended for use with D-10 series guns only. Virtually identical to BK-5M but without streamlined give. Complete round weight is 24.1 kg with projectile weighing 13.475 kg. Otherwise specifications almost identical to BK-5M YUGOSLAVIA , FEDERAL REPUBLIC Manufacturer Yugoimport SDPR Type: HEAT-T M69 Description: Probably no longer in production. Weight given as 26 kg