"3. Proving grounds trials.
Trials were, at first, done with a 45 mm blunt-nosed shell from the anti-tank gun, then with DK bullets.
Only one shot was fired from the gun, with impact velocity of 533.8 m/sec, which is equivalent to the minimum requirement from GABTU for 30 mm armour. After the shell hit, the plate cracked into 8 parts. Photographs of these parts are shown in figures 4, 5, and 6. Figures 4 and 5 show the place where the shell hit and the nature of the damage to the plate from the front and rear. Figure 6 shows the fracture type on the fragments. The crack is shiny, crystalline, with burrs.
One of the fragments was then trialled with a DK bullet, fired at a speed of 823.2 m/s, from a distance of 100 and 50 meters. The results of the trials are as follows.
- 100 meters. Hits: 2. Damage: 1 #11 and 1 #13.
- 50 meters. Hits: 4. Damage: 1 #11, 1 #15, 1 #13 from hitting the location where the armour was prepared for a Brinell test, and one #13 from hitting the welding seam.
- C = 0.27
- Cr = 1.54
- Ni = 2.32
- Mo = 0.34
Those insisting that the Germans sent a bad tank on purpose should read the 1942 PzIII tests where the armour also cracks (although not as catastrophically) and the front armour screen falls off.
For an idea of what ranges this would come into play at, a model 1932 45 mm AT gun's BR-240 shell flies at 546 m/s at 1500 meters and at 529 m/s at 1600 meters. Therefore, a the armour sample was hit from an equivalent of nearly 1600 meters, almost twice as much as the maximum distance attempted in the test. According to Soviet mathematical calculations, the PzIII should be vulnerable from the side until 1100 meters, but in reality was vulnerable from a distance in excess of 1600 meters. Looks like German armour fell short of Soviet standards.