U-5TS

U-5TS
U-5TS tank gun on display at the Motovilikha Plant Museum in Perm. Russia.
Type	Tank gun
Place of origin	Soviet Union
Service history
In service	1961
Used by	Current and former users:  Soviet Union  Afghanistan  Algeria  Angola  Belarus  Bulgaria  Cuba  Egypt  Eritrea  Ethiopia  Iran  Iraq  Iraqi Kurdistan  Israel  Kazakhstan  Mongolia  North Korea  Sahrawi Arab Democratic Republic  Russia  Syria  Tajikistan  Turkmenistan  Ukraine  Uzbekistan  Vietnam  Yemen Lebanese Christian Militia
Wars	Sino-Soviet border conflict Yom Kippur War Ethio-Somali War Soviet war in Afghanistan Lebanese Civil War 1982 Lebanon War Chadian–Libyan conflict Polisario War Angolan Civil War Ethiopian Civil War Iran-Iraq War Ethiopian-Eritrean War Gulf War First Chechen War Second Chechen War Operation Iraqi Freedom South Ossetia War (2008) Libyan Civil War Syrian civil war War in Afghanistan (1978–present)
Production history
Designed	Late 1950s
Specifications
Caliber	115 millimetres (4.53 in)
Rate of fire	6-10/minute
Muzzle velocity	1600 m/s (APFSDS)
Effective firing range	2000m high target - 1,870m; 3m high target - 2,260m; 4000m AT-12 missile.

The U-5TS (production designation 2A20) tank gun is a 115mm-calibre weapon that was fitted 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.

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 was too heavy to be easily 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.

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 a 1000 metres and re-established a comfortable penetration capacity against Western armor.

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.