Saturday, March 28, 2015
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.