Tuesday 28 October 2014

85 mm Gun Range

I talked about the doctrine of applying heavy guns of the IS-2 and ISU-152 from a long range (1500-2000 meters). What about lower caliber weapons, such as the 85 mm gun? The 5th Guards Tank Army has us covered, with its "Brief instructions several issues of using units of the 5th Guards Tank Army, arising due to partial reorganization of tanks and artillery in the army", dated May 21st, 1943, publied in Collection of Combat Documents from the Great Patriotic War, vol. 15, doc. 4.
The contents of the document are as about as brief as the title, but all the way at the bottom lies the answer to this question.

"Additionally, corps commanders should be aware that a 85 mm gun battery from the 6th AA artillery division has been assigned to each corps to assist in fighting enemy tanks, specifically T-6 (Tiger), tasked with fighting the enemy at long range (1500-2000 meters). Remember that the 85 mm gun is capable of penetrating any German tank at 1500 meters and knocking it out at 2000 meters. The one exception to this is the T-6 when hit in the mantlet and front. When hit in the side, turret, suspension, the T-6 is knocked out from 2000 meters by 85 mm guns just like any other German tank."


  1. "Remember that the 85 mm gun is capable of penetrating any German tank at 1500 meters and knocking it out at 2000 meters."

    Uhhh, okay. But then what's the difference between "Penetrating" and "Knocking out"?

    Also, this document mentioned that the 85mm AA Gun (possibly the 85mm 52-K Model, which in turn developped into the D-5) could knock out the Tiger from 2000 meters, which contradicts to the range test in your earlier blog post that saw the Tiger being penetrated at around 1400 meters.

    What's the explanation on this? Different shell? Different Gun? or probably difference between experience received from the Range test and Field test?

    1. Read the last passage carefully. Infact it says that this can only be archived when hitting the Tigers sides. Front and turretfront(Mantlet) is excluded!

      Also, T-6 = tiger.

      So it might make still sense.

    2. Penetrating: clear hole through the armour.
      Knocking out: spalling damage, knocking off tracks, etc

      Also 2000 meters is from the side.

    3. Both is from the side as written above Peter.

    4. Anyways, when was this document created?
      IMO it seems that the Panther didnt hit the battlefield yet, because its glacis is not penetrateable by this gun. Correct me if i am wrong.

    5. Pre-Kursk. So you are right the T-5 was not on the map at the time.

    6. I'm not sure how the Soviets define it, but US tanker Handbook (1941) predefine that following:

      Knockout: incapable to continue combat; tactical damage by fire, on turret, tracks, transmission or engine.

      Penetration: referenced a (ETO) engagement range, that the tank could being efficiently downed

      Didn't the Tiger had around 200mm (some areas) at the complete turret front (+gun mantlet) ?

    7. Yes the tiger turret front is practically Not much worse than the tiger IIs.
      Mantlet is between 90-150mm, armor behind the Mantlet 90-100mm.

    8. The Tiger II is a lot better. But the Tiger I's turret is 100-140mm with the structurally weak spots-opening bolstered by thicker armor. The armor behind is just in two supprort ribs with a large opening between and may not even be armor plate but structural steel (I don't know either way). A hit by a US Pershing (#40) 90mm T33 shot from 900 yds at the lower edge of the mantlet penetrated then deflected right through the support rib.

    9. Get some tiger books, the hole is rather smal, smaler than in wot. There is quite a big area with 100+100 or 90 mm. At some Spots even 135+100 mm.

      Ofc also the turret front is made of tank steel.

      For pics without the Mantlet check jentz and spielbergers books.

    10. "At some Spots even 135+100 mm."
      Sure. I have plenty of books. The cross-section shows the open area is about 2/3rds the front area. The turret front is described by Jentz as armored so it is 100m @ 15°. But that front turret armor is narrow and when the edge effect (see World War II Ballistics Armor and Gunnery, by L. Bird) is factored in only equivalent to ~50mm.
      Where the the 90mm T33 penetrated the turret the mantlet would be about 120-125mm.
      The edge effect multiplier there for 90mm shot is about 65% so that is 81mm. Together that is about 131mm while the 90mm T-33 would penetrate about 146mm @ 900 yds.

    11. for clarification, i was talking about WoT physics.

    12. For the 135 mm + 100 mm, this is from the pic i posted which is from the book you quoted. Its in the middle of the mantlet, obove and below the gun. The pics in the book show that the mantlet is still overlapping there.

      The area is rather small, so IRL not really relevant also because of the edge effect you mentioned. However, this is the maximum theoretical thickness of the turret front. Thats all :)

    13. You are right. That is the full line-of-sight distance. But, when RL hits are examined that penetrate where they probably shouldn't it has to be assumed something more is involved .

  2. Sorry, I didn't cite anything last time, here is the blog post I referred to