Armor piercing ammunition, as the name suggests, is used to penetrate body armor and light vehicle armor, and even heavy tank armor and reinforced concrete, depending on the size of the weapon. Armor piercing bullets are usually equipped with a sharp point and are filled with a heavy core (hardened steel or tungsten carbide) to improve armor penetration abilities. High-caliber weapons, such as those built onto combat aircraft, may employ rounds containing an even heavier depleted uranium penetrator, which spalls on impact, producing incendiary effects and furthering the damage.
The myth presented in some movies such as Ronin, that bullets may be rendered armor piercing by coating them with Teflon, is not true: armor piercing bullets are made from a particularly hard material such as tungsten, which would cause excessive wear to the lining of the barrel were the round not coated with a friction reducing material such as Teflon.
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