Wednesday 1 May 2013

45 mm APCR

By 1942, the penetrative power of the Soviet 45 mm anti-tank gun model 1932/37 has ceased to be very impressive. After studying captured German 37 mm PzGr 40 shells, and French 47 mm Komissan shells, NII-24 developed two types of APCR shells for it: one with a 20 mm tungsten carbide core, and one with a 28 mm tungsten carbide core. The shells were also manufactured with highly hardened steel cores. The requirements for the project were "penetration of a 60 mm armoured plate angled at 30 degrees, at a distance of 300-500 meters". Let's see how well they managed.

45 mm APCR type 1 (28 mm core, left) and type 2 (20 mm core, right). CAMD RF 81-12042-69

I will skip the metallurgical data, and get straight to the good stuff: penetration and accuracy.

The theoretical penetration calculations, against armour at 30 degrees, were as follows:
  • 0 meters: 80 mm
  • 100 meters: 74 mm
  • 200 meters: 69 mm
  • 300 meters: 65 mm
  • 400 meters: 60 mm
  • 500 meters: 56 mm
  • 600 meters: 52 mm
  • 700 meters: 48 mm
  • 800 meters: 44 mm
  • 900 meters: 40 mm
  • 1000 meters: 37 mm
In theory, the engineers met the requirement. At 400 meters, the shell penetrated 60 mm of armour. Let's see how that translates into practical penetrations.

"Armour plate: 50 mm, cemented. Shell type: 1. Core type: steel. Distance: 120 meters.

Result #1: dent. On the rear side, spalling 5-6 mm deep. The core is stuck in the armour plate.
Result #2: penetration. Diameter 60-80 mm entrance, 30-45 mm exit. Core is destroyed. The plywood behind the target has a breach 150 by 100 mm. 

Distance: 100 meters.

Result #1: Armour is not destroyed. A dent is formed on impact. The core is destroyed.
Result #2: Penetration. Entrance diameter 90-70, exit diameter 40-35 mm."

Well, the steel core APCR is inconsistent, to say the least. Let's see what tungsten can do.

"Armour plate: 50 mm, cemented. Shell type: 1. Core type: tungsten carbide. Distance: 700 meters. Result #1: penetration. Diameter of breach: 75-40 mm entrance, 35-45 mm exit. The plywood behind the target has a breach 160 mm by 110 mm. Similar results are achieved by shot #2.

Shell type: 2. Core type: tungsten carbide. Distance: 450 meters. Result #1: penetration. Diameter of breach 25-40 mm entrance, 20-35 exit. Plywood behind the target has a breach 80 by 100 mm. Similar results are achieved by shot #2."

Much better! Let's see how steel does against a thicker target.

"Armour: 60 mm, non cemented. Shell type: 1. Core type: steel. Distance: 100 meters.

Result #1: No penetration. A dent 40 mm deep is formed. The core shattered.
Result #2: No penetration. A dent 35 mm deep is formed. The core shattered."

And back to tungsten, with the same armour plate:

"Shell type: 1. Core type: tungsten carbide. Distance: 400 meters. Results #1 and #2: penetration. Breach size 40-75 mm entrance, [missing] exit. Plywood behind the target has a breach 400 mm by 150 mm. 

Shell type: 2. Core type: tungsten carbide. Distance  380 meters. Results #1 and #2: penetration. Breach size 25-35 mm entrance, 20-25 mm exit. The core shattered. First shot makes a breach in the plywood behind the target 50 by 80 mm, the second 80 by 80 mm."

At this point, the testers ditch steel, and only test tungsten for larger thicknesses.

"Armour: 80 mm, non cemented. Shell type: 1. Core type: tungsten carbide. Distance: 300 meters. Results #1 and #2: penetration. Breach size 50-90 mm entrance, 30-45 mm exit. The core shattered. 

Shell type: 2. Core type: tungsten carbide. Distance: 250 meters. Results #1 and #2: penetration. Breach size: 20-50 mm entrance, 20-18 mm exit. The core shattered."

These results are very promising, much better than the calculations. Let's see what happens against thicker armour.

"Armour: 100 mm, non cemented, at 0 degrees. Shell type: 1. Core type: tungsten carbide. Distance: 65 meters. Result: penetration. Breach diameter 65 mm entrance, 30-20 mm exit. The breach has fragments of the core stuck in it. The plywood behind the target is also penetrated.

Shell type: 2. Core type: tungsten carbide. Result: penetration. Breach diameter is a caliber."

This is very promising! Note the impressive thickness of the armour. The calculations have been very pessimistic, as the shell can penetrate 25% more armour than predicted. Such a shell can defeat a Tiger, provided the gun is close enough. 

Accuracy figures are also provided in the report. At 500 meters, the maximum deviation of type 2 shells is only 20 cm in either direction. Type 1 shells have poorer accuracy, with deviation of 42 cm vertically and 33 cm horizontally. The inaccuracy of type 1 shells is explained by their inconsistent mass. 

Something interesting to compare: along with captured German 37 mm shells, a document was captured describing them as only useful up to 300 meters. The realistic range for these 45 mm APCR shells is listed as 500 meters. Comparing penetration, the 37 mm PzGr 40 shells only penetrate a 30 mm armour plate at 30 degrees at 300 meters, and cannot penetrate a 40 mm plate. The 45 mm APCR shells could penetrate an 80 mm plate at 30 degrees at this distance. 

However, you may still be reeling from the suggestion that a 45 mm tank gun can take out a Tiger. A small caliber gun, on T-70 or even T-26 light tanks! Preposterous! Or is it?

CAMD RF 38-11377-12

"As a result of shooting the Tiger with a 45 mm tank gun, it is determined that:
  • a subcaliber shell penetrates the lower side hull, 62 mm thick, at 350 meters.
  • a subcaliber shell penetrates the upper side hull, 82 mm thick, at 200 meters."
CAMD RF 38-11377-12

"Photo #7. Penetrations from a 45 mm AT gun.
XX: penetration 20 mm in diameter, crack along welding seam 200 mm in length. Distance: 200 meters.
XXI: penetration 20 mm in diameter. Distance: 350 meters.

Photo #8. Penetrations from a 45 mm AT gun.
1: penetration, 30 mm in diameter. A crack formed from 50 mm from the breach to the edge of the armour plate.
5: penetration, 20 mm in diameter. Distance: 350 meters.

As a result of shooting at a Tiger with a 45 mm AT gun, it is determined that: 
  • a subcaliber shell penetrates the lower side hull, 62 mm thick, from 500 meters.
  • a subcaliber shell penetrates the upper side hull and turret side, 82 mm thick, from 350 meters."
Pretty impressive for such a small caliber!

11 comments:

  1. Never know that the 45mm can penetrate that much armor!

    By the way, Peter, which was the model of the gun used in the test? It seems to me that they used Model 1942 instead of Model 1937.

    ReplyDelete
    Replies
    1. The NII tests use a model 1932/37 AT gun. The T-70 uses a model 1938 tank gun. The second Tiger test is a model 1942 AT gun.

      Delete
  2. What is the count of that specific ammo usage in 1942,1943? Its production and logistical distribution. Do you have that data?

    I'm very interested in its usage (availability) in:
    -6th Cavalry Guard Corp, 201 tank battalion. (Feb. 16-28 1943, it was During Operation "Star" near Taranovka)
    -During Kharkov defence operations March 2 - 15, 1943.
    (In units 25. Guard Rifle division, 78. guard rifle regiment, near Taranovka)
    (104 rifle brigade near Pavlovka)
    (253 rifle brigade and 195 tank brigade near Rakitnoe)
    (62 guard rifle division, 1st Czechoslovakian separate Infantry battalion, near Sokolovo)

    If you don't know, do you know where can I search this (over the internet)? (I can manage with Russian language somewhat)

    ReplyDelete
    Replies
    1. This is some really specific stuff, I don't have any data on that. Ask on vif2ne.ru, it's a military history forum with lots and lots of experts on almost every period and war.

      Delete
    2. Thank you on your replies!

      Delete
  3. Forgot to say before, job well done with this site!
    Keep up the good work!!

    P.S.
    Where can I check online articles used in research by research institutes ? i.e. CAMD RF 38-11377-12...etc

    ReplyDelete
    Replies
    1. Sadly, the Central Archive of the Ministry of Defense of the Russian Federation has no online presence. If you want to get the original, you have to go to the physical archive itself.

      Delete
  4. P.P.S.
    Those last too pictures from the field, with penetrated Tiger.

    What is the angle of entry to them? 90 degrees?

    ReplyDelete
    Replies
    1. Unless otherwise specified, it's always 90 degrees.

      Delete
  5. I found this posted on the blog just 13 days later:

    "The 45 mm model 1942 gun isn't quite that accurate (model 1932 and 1937 results are identical):
    •APCR shell Br-240P
    ◦Vertical: 50 cm
    ◦Horizontal: 50 cm
    ◦Trend: horizontal and vertical deviations grow at the same rate."

    So is it "At 500 meters, the maximum deviation of type 2 shells is only 20 cm in either direction." 40cm or 50cm?

    -Mo--

    ReplyDelete
    Replies
    1. 1) The article you are citing has dispersion for 1000 meters. This one has dispersion for 500 meters.
      2) Different shells have different dispersions, even in the same gun.
      3) "20 cm in both directions" means 20 cm horizontal and 20 cm vertical, not 40 cm.

      Delete