Object 701-4, blowing out your transmission while still looking cool!

Would you like to see the Object 701-4 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 another IS-4 Prototype! This is the Object 701-4!

The Object 701-4 looking a bit worn down and very menacing

Quick note:

The name Object 701-4 is more an English version of the original name of the tank. The actual name is Объект 701 № 4.
As you can see in Russian the Prototypes are given a number, and this one is Number 4. But on the English side of the internet the 701-4 seems to be more widely used. And me having to constandly say Number 4, or No 4 might get a bit confusing. So I’m using Object 701-4 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 fifth 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 701-4) was build in parallel with the older IS-4 Prototypes, Object 701-1 and Object 701-2 while those were being re-build with new improvements.

The Object 701-4 was the first of the IS-4 Prototypes to be built based on the results of the firing trials done on the previous prototypes. And so this tank is the first with thicker armour then all the others.

A big change was the upper glacis of the hull. Instead of it being 120mm thick, it was changed to 140mm. Another important change was the thickness of the turret armour, it went from 160mm thick to 200mm thick, all around!

Unlike the previous prototype where they tested a 100mm gun on the tank, this tank was armed with the 122mm S-34-II gun again, just like the first prototypes.

The 122mm S-34-II was an experimental gun based on the 100mm S-34 gun. It was made as replacement for the D-25T. The S-34-II had a few big improvements compared to the D-25T:

  • The gun was more rigid and allowed for more accurate fire.
  • The lack of a muzzle brake reduced the size of the smoke comming out of the gun when firing, and also made it safer for infantry to be standing next to the gun when firing.
  • The gun was fitted with a projectile rammer which increased the rate of fire.
  • A device was fitted that would blow air through the gun after it had fired, which reduced gas contamination inside of a tank turret.

So with all those improvements, why was the gun not used on any other tanks? Well that is because this gun required the gunner to be on the right of the gun, and the loader on the left. And on all other tanks with the D-25T it was the other way around. So this would have required a redesign for any tank that wanted to use this gun. And in the end it was cheaper to use the D-25T instead of redesigning all tanks with 122mm guns fitted.

The tank was assemled November of 1944. She was send out for a 1000km testing drive. But just 103km into the test the transmission gave out, and so the Tank was stuck in a field without a transmission. It was in Early December when the tank was recovered.

After this failed test there really isn’t anything else about the Object 701-4 that is mentioned in sources. So sadly this is where it ends for this tank.



I would love to see this, or any other, IS-4 Prototype ingame. It’s weird to say this but the biggest reason I want this one ingame is because it looks so badass on the only photo we have of her. It just looks so menacing!

This one being almost like the IS-4M we have ingame (Armour wise that is) makes me think of it as a good techtree or premium vehicle. But let me know what you think in the poll above!

To wrap things up let’s compare this one to the ingame IS-4M:

Object 701-4 <|> IS-4Minnmm

4** <|> 4**
750hp V12 <|> 750hp V12
Suspension Type
Torsion bar <|> Torsion bar

Main armament
122mm S-34-II <|> 122mm D-25T
Vertical guidance
-3° to +19° <|> -3° to +19°
Rate of fire (Rounds per minute)
2,3 - 4 <|> 2,2 - 3

Secondairy armament
mmmi7.62mm DT <|> 2 x 12.7mm DShK

Turret armour
~400mm <|> ~400mm
200mm <|> 250mm
200mm at 20° <|> 200mm at 35°
200mm at 30° <|> 170mm at 35°
30 - 45mm <|> 30 - 50mm

Hull armour
Frontal Upper Glacis
140mm at 61° <|> 140mm at 61°
Frontal Lower Glacis
160mm at 45° <|> 160mm at 45°
Upper Sides
160mm at 30° <|> 160mm at 30°
Lower Sides
160mm at 0° <|> 160mm at 0°
Rear plate above the Transmission
100mm at 37° <|> 100mm at 37°
Rear Upper Glacis
120mm at 32° <|> 100mm at 32°
Rear Lower Glacis
120mm at 40° <|> 100mm at 40°
Engine Deck
30mm <|> 30mm
28mm <|> 30mm

** = On the IS-4M the gunner and commander sit to the left of the gun and the loader to the right. This is swapped on the Object 701-4.



Ammunition layout of the Object 701-5. The Object 701-4 is identical 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 S-34-II gun
    • Vertical guidance: -3° to +19°
    • Rate of fire: Around 3-4 rounds per minute
    • Ammunition storage: 30 rounds
    • Ammunition types: Most likely the same as the D-25T, just not the post war BR-471D round.
  • Secondairy armament: 7.62mm DT machine gun


  • Turret:
    • Mantlet: 400mm effective armour when hitting it above the barrel
    • Front: 200mm at various angles
    • Sides: 200mm at 20°
    • Rear: 200mm at 30°
    • Roof: 45mm

  • 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: 120mm at 32°
    • Rear Lower Glacis: 120mm at 30°
    • Engine Deck: 30mm
    • Bottom: 28mm

** = It’s possible that the armour was thinner at 140mm thick at the rear around the transmission. Something like this is mentioned in a source but is not very clear about it.

That is all for now! Hope you enjoyed reading about this unique prototype.

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
  • Object 701-5, this is the last IS-4 prototypes with the S-34-II gun.
  • Object 701-6, this is the pre-production IS-4.



Primary source:

Secondairy sources:

Extra sources:

S-34-II gun:



+1 as a mid tier squadron option, as its status as a fully built prototype makes it an excellent candidate for that placement.


Absolutely +1. Sucker for anything prototype (especially “Object” named) and this is without a doubt my favorite of all the IS-4 prototypes.