Tuesday 4 December 2018

SU-100 Review

"March 12th, 1945
Comments on the use of the SU-100 SPG in combat
  1. During the fighting of the Corps from January 14th to March 10th, 1945, SU-100 SPGs were used as tanks, as the Corps fought in operative depth and was almost entirely equipped with SU-100 SPGs.
  2. The off-road mobility of the SU-100 is reduced compared to the T-34 tank, due to the increase in weight and shifting of the center of mass forward due to the longer gun and thickening of the front armour. This adds additional load on the front wheels.
    When crossing obstacles off-road, the gun can strike the ground and then the barrel bursts when firing. The gun mount can shift during sudden turns and driving on uneven terrain. There were cases of a complete breakaway of the elevation mechanism.
  3. The crew's work is difficult:
    1. The crew compartment is smaller due to the larger gun.
    2. The gun sight is shifted towards the gun (it's uncomfortable for the gunner to aim). It's almost impossible to correct fire with the hatch closed.
    3. The fighting compartment limits the loader's movement, which affects the rate of fire.
  4. The average combat rate of fire of the SU-100 is 4-5 RPM. The placement of the ammunition under the gun makes the crew's work difficult.
  5. The quality of armour is satisfactory, but the quality of welding is not satisfactory. Welding seams burst when the hull is hit.
  6. The biggest defects of the SU-100 are:
    1. The elevation mechanism gear teeth can break during firing.
    2. The oil pipe from the oil filter to the stop valve can break. The causes of the breakages are vibration during movement, thin walls of the pipe, brittle metal.
    3. Breakage of ball bearings of the front road wheels and layering of the rims due to the shifting of the center of mass and causing additional load.
    4. Insufficient robustness of the hull welding seams.
    5. A reduction of fuel capacity by 170 L reduces the range compared to the T-34.
    6. A lack of machinegun makes fighting infantry difficult, which makes the SPG a poor substitute for tanks.
    7. The rear plate of the casemate is thin.
    8. The narrow horizontal traverse angle makes firing at moving targets difficult.
  1. The qualities of the SU-100 are superior to that of the SU-85, both the firepower and the technical qualities, but are inferior to that of the tank.
  2. It is necessary to introduce some design changes:
    1. Reinforce the ball bearings of the front wheels, since reinforcement of the springs did not have the desired effect.
    2. Install a new oil pipe for starting up in the winter. Add a carrier in the middle for it.
    3. Increase the capacity of fuel.
    4. Reinforce the elevation and turning mechanisms, as well as their carriers.
    5. Give the commander a machinegun and increase the traverse angle.
  3. It is reasonable to use the SU-100 as an SPG for escort of tanks, but not as a tank.
Chief of Staff of the 1st Guards Tank Corps, Guards Major-General of the Tank Forces, Savchenko
Chief of the Operational Department, Guards Lieutenant-Colonel German
March 12th, 1945"


  1. So basically in 1945 the Soviets had the best mobile anti tank gun in the world. And a enemy who was no longer in any shape to go on the offensive.

    1. Yes, some people argue that at no point during the war did the SU-100 actually perform a task that the SU-85M would not have performed just as well.

    2. It seems to me that the SU-100's service career was roughly akin to that of the KV-85; both were good ideas as concepts but imperfectly executed solutions to get a more mobile capable AT gun than that then carried by the Red Army's medium tank to the battlefield.

      The introduction of the T-34/85 had raised the question of "what's the point?" for the KV-85 and the new IS-1, as well as the SU-85 and SU-85M (well, save for the fact the SU-85M did have better hull armor). The SU-100 was thus a logical extension of the T-34/85, and was designed to fight German heavies, but once you start equipping the new T-44 and T-54s/55 designs with 100 mm D-10 guns then the question again arises of "what's the point?" for the SU-100. The very idea of the turretless assault gun/tank destroyer in WW2 is that you can mount a larger caliber/higher velocity/more capable AT gun directly on the tank chassis than you can on the turret, to create a vehicle which fights just as well if not better than the tank defensively and is cheaper to built. Once the main battle tank has the same weapon as the turretless vehicle, then the turretless vehicle is just a less capable (though still admittedly less expensive) weapon.

      I will say in favor of the SU-100, and to the point that they were 'not needed', is that it shows that by 1944 the Soviets were anticipating Axis countermoves, as one of your articles correctly states. If Germany had managed to build more King Tigers, Jadgtigers, Jadgpanthers, Panther IIs, or whatever "what if" armchair historians suggest, the Russians would have countered with more SU-100s, IS-2Us, IS-3s/IS-4s, ISUs with the 130 mm or higher-powered 152 mm guns, and T-44s. There would have been no long-lasting German advantage.

    3. True, a lot of Panzer '46 fanfiction is based on the fact that the Germans somehow magically move from napkin sketches to full scale production within months, while ignoring the fact that by May of 1945 the IS-3 was already in production, the T-44 was in production, and viable prototypes of the T-54 and IS-4 already existed.

    4. The 85mm gun fell short if facing Panthers or Tigers, and was not so suitable to perform the role of overwatch, IMO it was useful, but it is true that by the time it was introduced the Germans were finished anyway.

    5. And on the other front the Centurion and M26 were entering production while the Germans were the only ones losing infra at a hair-raising pace (to bombers and advancing land armies alike) and unable to give more than the most rudimentary training to new recruits anymore.

      But then for that kind of alt-history Step One is "Ignore Facts" anyway. It's depressingly common even outside the Wehraboo circles really as authors of pseudohistorical fiction tend to be violently allergic to paying attention to all the inconvenient limitations and details real leaders and empires had to grapple with.

    6. I would of hated to see the crews of those German "Super tanks" in 1946 fantasy games. 1 veteran of regular age along side a few 10 year old kids and grandpa.