Ammunition

The Germans were not content merely to increase the size of their tank guns, they also developed the ammunition. The main AP round (pz gr) was an armour-piercing shell containing a small HE charge. All tanks were equipped with this type plus ordinary HE (Sp gr) ammunition. With the introduction of the 5cm gun, a capped AP shell (APC) was produced in order to improve performance against face-hardened armour. This was additional to the ordinary 5cm AP shell. For guns of 7.5cm calibre and over, a ballistic cap was fitted in addition to the armour-piercing cap (APCBC). This improved performance at long range, by giving the projectile a better ballistic shape. Since the AP cap was enclosed, it was possible to make it blunter and so improve performance at oblique attack without deterioration in its ballistic properties. For low-velocity guns, hollow charge ammunition was produced. The projectile penetrated armour plate by means of a concentrated forward blast, which meant that performance was independent of striking velocity and, therefore, to a large degree, independent of range. To give very high performance at short ranges, the Germans introduced the AP40 shot. This had a small, very hard tungsten-carbide core in a mild steel envelope. Only the core penetrated. This ammunition was even produced for the 8.8cm gun, although the projectile weighed only 16lb.

Armoured-piercing cap: This consisted of a hard steel cap fitted to armour-piercing projectiles to assist penetration of face-hardened armour. A projectile so fitted was known as APC. All German AP projectiles of 5cm and over, had a piercing cap, and in calibres of 7.5cm and over, this was of a blunt shape making a ballistic cap necessary.

Ballistic cap: This was a long and pointed cap fitted to a projectile to reduce air resistance in flight. (Where both armour-piercing cap and ballistic cap were fitted, the projectile was designated APCBC.) In the case of normal AP projectiles, the presence of a ballistic cap, although in itself slightly impeding penetration, actually increased it at medium and long ranges, because of the reduced deceleration by air resistance, and consequent higher striking velocity.

AP40 (Pzgr 40): This was a special type of AP ammunition used with most German tank and anti-tank guns, in addition to the more conventional types of AP projectile. The AP40 consisted of a mild steel body, a light alloy or plastic ballistic cap, and a cemented tungsten carbide core. The weight of this type of projectile was only 50-65 per cent of that of the normal AP shell. The MV was high, but the velocity dropped rapidly with increased range, so that increased penetration was obtained at short ranges only.

Hollow charge shell: This type of shell had a shaped cavity in the forward end of the HE filling. The effect on impact was to concentrate a jet of blast in a forward direction. The object being to pierce armour by blast perforation instead of the projectile forcing its way through the armour by its weight and striking velocity. The penetrative power of hollow charge AP projectiles was, therefore, independent of the striking velocity. Their use in low-velocity weapons, such as howitzers or infantry guns, gave these weapons an improved performance against tanks, within the limits of their accuracy.