Tuesday 29 April 2014

ZiS-5 (3-K)

Aside from the ZiS-5 we know and love, there was another project with this designation, which started in early 1941. The gun was based on the 3-K model 1939 76 mm AA gun, and was noticeably longer than the ZiS-5 that ended up on the KV in late 1941.


Based on trials of the experimental 76 mm tank gun (ZiS-5) in a KV-1 turret, tested over 612 shots and 170 km, ANIOP has come to the following conclusions:
  1. The robustness of the system in general is satisfactory. The factory must increase the robustness of the breech wedge by increasing the quality of the metal, as there was a dent in the lower part of its bearing surface.
  2. The recoil mechanisms of the model 1940 tank gun [F-34] (without a compensator) used in the ZiS-5 system performed satisfactorily, and may be used in this gun system. The factory must improve the return mechanism valve due to its unreliability (when checking pressure, air and fluid can escape through the valve).
  3. The semi-automatic mechanism worked perfectly. There were no breakdowns or deformations. The elevation and trigger mechanisms are reliable, and worked perfectly. The factory must:
    1. Balance the oscillating part of the gun such that the effort required to lower the gun is decreased (effort reached 9-12 kg). 
    2. Turn around the elevation mechanism handle and put it closer to the sight for more convenient work.
    3. Put the firing mechanism lever closer to the elevation mechanism for more convenient work.
  4. The model 900 telescopic sight performed satisfactorily, and can be used with the ZiS-5 gun in the KV-1 turret.
  5. The deviation at 1000 meters is satisfactory:
    1. Shooting with AP shells:
      1. Vertical deviation: 0.17 - 0.24 m
      2. Horizontal deviation: 0.16 - 0.2 m
    2. Shooting with HE shells:
      1. Vertical deviation: 0.29 - 0.34 m
      2. Horizontal deviation: 0.18 - 0.35 m
  6. The gun has insufficient depression (-2 degrees), which is less than required (-5 degrees).
  7. The gun's length does not impede maneuverability. The gun is not afraid of dirt during marches.
  8. Only 44 testing shells were fired. The testing program requires 180 such shells. 120 various special shells that are mentioned in the report body do not give sufficient information about the robustness of the system when firing special shells, as the mount was loaded 14.5% less than required.
    The possibility of using a special shell with this system is doubtful, as the force of resisting recoil reaches 16,000 kg (at the end of the recoil), which is twice as much as calculated. The factory must revise the recoil mechanism in order to make the resistance uniform through the entire path when shooting with a special shell.
Based on the results of the trials, ANIOP has come to the following conclusions:
  1. The 76 mm ZiS-5 tank gun in the KV-1 turret passed trials. After removing the defects in the report, the gun can begin production.
  2. The feasibility of using special shells is still undetermined. Additional trials must be done using a special charge at a temperature of 40-50 degrees (at a rate of fire of 4-5 RPM), 100-120 shots in total. This can be carried out by the GAU military representative at the factory proving grounds."


  1. "The gun is not afraid of dirt during marches." Soviet gun stronk!

  2. So it is more accurate than the F-34 gun.

    1. The barrel is longer, so it is to be expected.

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