Object 701-6, the Pre-Production IS-4

Would you like to see the Object 701-6 ingame?
  • Yes.
  • No.

0 voters

How would you like to see it added ingame?
  • As a researchable vehicle.
  • As a premium vehicle.
  • As an event vehicle.
  • As a squadron vehicle.
  • I said ‘No’ in the first question.

0 voters

Hello everyone! Today I’m going to suggest the final prototype (Pre-Production) IS-4! This is the Object 701-6!

The Object 701-6 parked on a road, note the different drivers hatch/vision slot compared to the normal IS-4

Quick note:

The name Object 701-6 is more an English version of the original name of the tank. The actual name is Объект 701 № 6.
As you can see in Russian the Prototypes are given a number, and this one is Number 6. But on the English side of the internet the 701-6 seems to be more widely used. And me having to constandly say Number 6, or No 6 might get a bit confusing. So I’m using Object 701-6 to be as clear as possible.

And incase you are wondering, there are seven total IS-4 Prototypes! From the Object 701-0 up to the Object 701-6!

With that out of the way, let’s continue!



The story of this tank began in 1944, she was the sixth IS-4 Prototype made. If you want to read more about the origins of the IS-4 Prototypes then check out my post on the first Prototype:

This tank (The Object 701-6) kind of started out at the Object 701-2. In a way tho. When the Object 701-2 was done being used for tests, she was taken apart and re-build into the Object 701-6. A hard factory reset if you will.

Unlike all the previous IS-4 Prototypes this tank was the first to be armed with the 122mm D-25T gun instead of the Experimental 122mm S-34-II that was used on the other Prototypes. At the later stages of the IS-4 Prototypes being made the choice to use the D-25T gun for the future Production models was already made. Sadly the superior S-34-II was not going to be put on any other tanks.

In Early April of 1945, the tank was at the Kirov plant where she would be going through some final Tank tests. During these tests two problems were encountered, one with the clutch and one with the engine oil, but both problems were solved right away.

The tank succesfully drove for 548km during some pretty bad weather. But even with the bad weather the tank performed reliably.

And that is where the story for this tank ends. Not exactly an exciting story for a tank, but then again Pre-Production Prototypes tend not to be very exciting :P
Maybe the drivers hatch was changed and the tank became a Production model, anything is possible really.



I would love to see this, or any other, IS-4 Prototype ingame. This one is not the most exciting, but still worth suggesting. The more IS-4’s the better! :P

So what is the difference between the Object 701-6 and the IS-4M that we have ingame?
Ignoring the different side skirts and other very small changes that the IS-4 got when it was modernized into the IS-4M, the only difference that can be pointed out is the drivers hatch/vision slot.

The Production versions of the IS-4 would get a much smaller hatch/vision slot that also proved to be much stronger against incomming shells. Instead of the vision slot being in front of the eyes of the driver like we see on the Object 701-6, on the Production IS-4’s this would be changed to two optics being put on the drivers hatch. With the vision slot gone this forward bulge could be made much stronger.

This one being almost identical to the IS-4M we have ingame makes me think of it as a nice event vehicle. But let me know what you think in the poll above!



Longitudinal cross section of an Production IS-4, aside from the Drivers area the Object 701-6 is indentical to it

Basic stats:

  • Crew: 4 (Commander, Driver, Gunner, Loader)
  • Powerplant: 750hp V12
  • Suspension Type: Torsion bar
  • Turret traverse while targeting: 7,5 degrees/second
  • Maximum possible turret traverse: 15 degrees/second


  • Main armament: 122mm D-25T gun
    • Vertical guidance: -3° to +19°
    • Rate of fire: Around 2,2 - 3 rounds per minute
    • Ammunition storage: 30 rounds
    • Ammunition types: APHE, APHEBC, APCBC, HE
  • Secondairy armament: 2 x 12,7mm DShK machine guns


  • Turret:
    • Mantlet: 400mm effective armour when hitting it above the barrel
    • Front: 250mm at various angles
    • Sides: 200mm at 35°
    • Rear: 170mm at 30°
    • Roof: 30-50mm

  • Hull:
    • Frontal Upper Glacis: 140mm at 61°
    • Frontal Lower Glacis: 160mm at 45° + spare track links
    • Upper Sides: 160mm at 30°
    • Lower Sides: 160mm at 0°
    • Rear plate above the Transmission: 100mm at 37°
    • Rear Upper Glacis: 100mm at 32°
    • Rear Lower Glacis: 100mm at 30°
    • Engine Deck: 30mm
    • Bottom: 30mm

Front cross section cross section of an Production IS-4, the Object 701-6 is indentical to it

The Object 701-6

That is all for now! Hope you enjoyed reading about this pre-production IS-4.

Make sure to leave a vote in the poll above!

Also be sure to check out all the other IS-4 Prototypes I’ve suggested:

  • Object 701-0, this is the first IS-4 prototype.
  • Object 701-1, this one has a 50mm mortar added.
  • Object 701-2, this one is armed with a 100mm gun!
  • Object 701-3, this was used for firing trials. (This thread is not a suggestion, but just a normal post)
  • Object 701-4, this was one of the last IS-4 prototypes
  • Object 701-5, this is the last IS-4 prototypes with the S-34-II gun.
  • Object 701-6



Primary source:

Secondairy sources:

Extra sources:

D-25T gun:


1 Like

Looks better than the in-game IS-4m, the angles look clean cut and armour quality looks better.


Gonna throw a curveball and say squadron to add a lower tier squad, or if it must, foldered under the IS4M. Looks beautiful tbh. Armor would be super trolly in game though