The U-5TS (production designation 2A20) tank gun is a 115mm-calibre weapon that was fitted almost exclusively to the Soviet Union's T-62 main battle tank. It was the first smoothbore weapon designed for tanks, and heralded the change in main armament from rifled cannons.

History

As the T-54/55 series began to replace the T-34 tanks in the Soviet Army in the 1950s it was recognised that the standard NATO tanks of the time—the Centurion and M48 Patton—had armour that could not easily be defeated by the existing ammunition for the 100mm D10 gun that the new tanks carried. The Soviets set about designing a new "heavy" vehicle which was required to complement the tanks in an overwatch capacity and to provide greater anti-armour capability.

T-62 Tank with U-5TS Gun at the US NTC

The new vehicle, the T-62, was to be equipped with a new smoothbore design—which allows higher velocity and greater armour penetration with kinetic rounds—based on an enlargement of the 100mm 2A19 anti-tank gun that had entered production in 1955. The new weapon, designated as U-5T, could penetrate 300mm of vertical RHA at 1,000 metres and re-established a comfortable penetration capacity against Western armour.

Though the T-62 would have variable success in the conflicts it was involved in, the U-5TS would remain a formidable weapon that proved capable of penetrating the armour of any comparable NATO tank until the deployment of third generation MBTs in the late 1970s and early 80s. This was proven by examination of Iranian Chieftain and M60s knocked out by Iraqi T-62s during the Iran–Iraq War. These examinations led to the development of add-on armour packages such as Stillbrew to try to counter the U-5TS.

Ammunition

Another first with this gun was the use of armour-piercing fin-stabilized discarding-sabot ammunition, with the initial 3VBM-1 rounds featuring steel penetrators. The subsequent development of this type of ammunition for this gun led to an array of penetrator designs and different materials with the final model, the 3UBM-13, using depleted uranium. In accordance with later Soviet and current Russian practice an anti-tank guided missile, the 9K118 Sheksna, has been developed for use with the T-62 and U-5TS. There is also HE-FRAG and HEAT ammunition available for this weapon.

Due to the comparatively low height of the T-62 design - in line with Soviet tank design philosophies of the time - the U-5TS is limited to a rate-of-fire of 6-10 shots per minute due to little room for the loader to perform his activity. Experienced loaders were capable of reloading the gun in 6 seconds.

DesignationOriginDesigner & producerYearSub-projectile lengthPenetrator dimensionL/D ratio (sub-projectile / penetrator only)Penetrator material & weightSub-projectile weight with sabot / Projectile WeightPropellant type & weightChamber pressureMuzzle velocityVelocity dropPerforation at normal and oblique incidencesNotes
3BM-3Soviet UnionOAO Zavod1963542mm (21.3in)⌀ 42-30 × 436mm12.5:1 (avg. diameter to penetrator length)Steel Rod5.5kg / 4.0kg1615m/s128.5m/s (at 1000 m)270mm at 0° at 2000 m, 100mm at 60° at 2000 mHas Tungsten Carbide Tip
3BM-4Soviet UnionOAO Zavod1963542mm (21.3in)⌀ 42-30 × 436mm12.5:1 (avg. diameter to penetrator length)Steel Rod5.5kg /???kg1650m/s128.5m/s (at 1000 m)220mm at 0° at 2000 m, 110mm at 60° at 2000 mDoes not have the tungsten carbide tip
3BM-6Soviet UnionOAO Zavod1967542mm (21.3in)⌀ 42-30 × 436mm12.5:1 (avg. diameter to penetrator length)Steel Rod5.34kg / 3.86kg1680m/s128.5m/s (at 1000 m)240mm at 0° at 2000 m, 120mm at 60° at 2000 mDoes not have Tungsten Carbide Tip
3BM-21Soviet UnionOAO Zavod1975Steel Rod6.26kg /???kg1600m/s128.5m/s (at 1000 m)330mm at 0° at 2000 m, 135mm at 60° at 2000 mFeatures Tungsten Carbide Tip with a Tungsten Alloy Piercing Cap
3BM-28Soviet UnionOAO Zavod1978⌀ 30mm avg. × 326mm10.8:1 (avg. diameter to penetrator length)Depleted Uranium Rod4.91kg /???kg1650m/s95m/s (at 1000 m)350mm at 0° at 2000 m, 205mm at 60° at 2000 mThe Penetrator was later re-used to make the 125mm 3BM-29 APFSDS. Penetrator Weight = 4.36kg
3BM-36Soviet UnionOAO Zavod1988⌀ 28mm avg. × 380mm13.5:1 (avg. diameter to penetrator length)Depleted Uranium Rod???kg /???kg1650m/s80m/s (at 1000 m)385mm at 0° at 2000 m, 225mm at 60° at 2000 mThe Penetrator from 3BM-32 Vant was re-used to make the 3BM-36. Penetrator Weight = 4.3kg
BD/36-2Great BritainRoyal OrdnanceHeavy Tungsten Alloy Rod5.93kg / 3.59kg1600m/s55m/s (at 1000 m)385mm at 0° at 2000 m, 225mm at 60° at 2000 mThe 115mm BD/36-2 APFSDS-T round has a tungsten-nickel-iron penetrator derived from the design of the British 105mm H6/62 APFSDS-T. Made for Egyptian Production.
M1150BelgiumMecar (subsidiary of Nexter Systems)Heavy Tungsten Alloy Rod6.5kg /???kg1635m/s>500mm LOS at 60° at 2000 m
3BM-21MRussia⌀ 22 × 640mm26:1Heavy Tungsten Alloy Rod???kg /???kg1610m/s65m/s (at 1000 m)490-495mm at 0° at 2000 m, 285-290mm at 60° at 2000 mNew 115mm in Development. Appears as a 3BM-60 Svinets-2 penetrator inside a 115mm projectile.

Current and former users

See also

Weapons of comparable role, performance and era

Notes and references

  • Zaloga, Steven; Modern Soviet Combat Tanks; Osprey Publishing, London; 1984

External links