8.8 cm KwK 43

The 8.8 cm KwK 43 L/71 (Kampfwagenkanone —"fighting vehicle cannon") was an 88 mm 71 calibre tank gun designed by Krupp and used by the German Wehrmacht during the Second World War. It was mounted as the primary armament on the Panzerkampfwagen VI Ausf. B Tiger II and the 8.8 cm PaK 43, an anti-tank gun, was very similar in design and use albeit not mounted on tanks but rather on tank destroyers or deployed on the field.

At 6.24 m (20.5 ft), the length of the KwK 43's barrel was over 1.3 metres longer than of that of the 8.8 cm KwK 36 L/56 used for the Tiger I. The cartridge of the KwK 43's shell was also considerably longer (at 82.2 cm) and wider than that of the KwK 36's meaning that the KwK 43 allows for more room for a heavier propellant charge in its shells than the KwK 36 could. All guns of the PaK/KwK 43 series could use the same ammunition interchangeably.

The KwK 43 and PaK 43 were initially manufactured with monobloc barrels meaning the barrel was made from one piece. However, due to the weapons' extremely high muzzle velocity and operating pressures when fired, the weapon suffered from accelerated barrel wear. As a result, the change was made to manufacture the PaK/KwK 43 with a two-piece barrel instead of a monobloc barrel. This had minimal to no effect on the performance of the gun, but made replacing a worn-out barrel much faster and easier than before.

In addition, the massively increased operating pressures of the new gun in turn required a new armour-piercing shell to be designed. The result of this was the PzGr.39/43 APCBC-HE projectile, which was similar to the older 10.2 kilograms PzGr.39-1 APCBC-HE projectile used by the 8.8 cm KwK 36 and PaK 43 guns except for the addition of much wider driving bands. The wider driving bands of the PzGr.39/43 increased the weight of the shell to 10.4 kilograms as a result. However, due to the full transition to the newer PzGr.39/43 rounds wasn't completed for some time, the older PzGr.39-1 rounds was instead allowed to be used for the KwK 43 & PaK 43 if provided the gun had fired no more than 500 rounds. Over that set amount, it was feared that the expected barrel wear combined with the narrower driving bands of the PzGr.39-1 could lead to a loss of pressure in the gun. The new PzGr.39/43 could be fired without loss of pressure until the barrel was worn out, thus requiring no restriction.

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