ISU-122S

In later models the A-19 gun was modified to have a semi-automatic breech block. This gun was designated D-25S, and the vehicle mounting it ISU-122S. The modification increased rate of fire from 1.5 rounds/minute to 3 rounds/minute. The ISU-122S variant is recognizable by its ball-shaped gun mantlet and double-baffle muzzle brake.

ISU-122S
Class Vehicle
Type Armoured Fighting Vehicle
Manufacturer Factory No.100 Kirovskiy Works in Chelyabinsk
Production Period 1944 - 1945
Origin Russia (USSR)
Country Name Origin Year
Russia (USSR) 1944
Country Name Operational Year Retirement Year
Russia (USSR) View
ManufacturerName Production From Production To Quantity
Factory No.100 Kirovskiy Works in Chelyabinsk 1944 1945 1400 View
GENERAL DATA
Other DesignationsISU-122S
Manufacturer(s)Factory No.100 Kirovskiy Works in Chelyabinsk (ChKZ or Tankograd)
Production Quantityabout 14001Production Period1944-1945
TypeAssault GunCrew5
Overall Length9.8 m (32' 2")Barrel Overhang3.0 m (9' 10")
Width3.1 m (10' 2")Height2.5 m (8' 2")
Combat Weight46000 kg (101000 lbs)Radio Equipment10RF
FIREPOWER
Primary Armament122mm Gun D-25SAmmunition Carried20-30
Traverse (degrees)Manual (14°)Elevation (degrees)-3° to +16°
Traverse speed (360°)-SightTSh-17
Secondary Armament12.7mm DShK MG (AA)Ammunition Carried500


MOBILITY CHARACTERISTICS
Engine Make & ModelV-2-ISTrack Links87-90/track
Type & DisplacementV12, 38.9 litersTrack Width65 cm (26")
Horsepower (max.)600hp@2000rpmTrack Ground Contact436 cm (172")
Power/Weight Ratio13.0 hp/tGround Pressure0.81 kg/cm2 (11.5 psi)
Gearbox4 forward, 1 reverseGround Clearance0.46 m (1' 6")
FuelDieselTurning Radius0
Range on/off road150(230) kmGradient36°
Mileage on/off road350 l/100kmVertical Obstacle1.0 m (3' 3")
Fuel Capacity520 (+ 270 external)2 lFording1.3 m (4' 3")
Speed on/off road37/16 km/hTrench Crossing2.5 m (8' 2")
ARMOR PROTECTION
Armor DetailFrontSideRearTop/Bottom
Hull90mm@60°90mm@90°60mm@49°20mm@0°
Superstructure60mm@12°(glacis)75mm@75°60mm@41°30mm@0°
90mm@60°60mm@90°
Mantlet100mm@round---
NOTES
1Total ISU-122, ISU-122S and ISU-152 production is claimed to be 4075 by June 1945 by Zaloga. The estimate provided here assumes 25% of 1944 production and 50% of 1945 production.
2It is assumed here that three 90 liter tanks are used for fuel.

BP22, ST, RTAV, RT, IS2, Russian Military Zone

https://en.wikipedia.org/wiki/ISU-122

End notes