14mm

The 14.5×114mm (.57 Cal) is a heavy machine gun and anti-materiel rifle cartridge used by the Soviet Union, the former Warsaw Pact, modern Russia, and other countries.
It was originally developed for the PTRS and PTRD anti-tank rifles, but was later used as the basis for the KPV heavy machine gun that formed the basis of the ZPU series anti-aircraft guns that is also the main armament of the BTR series of armoured personnel carriers from the BTR-60 to the BTR-80 and for heavy anti-materiel sniper rifles.

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