The Anti-tank rifle reference article from the English Wikipedia on 24-Apr-2004
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Anti-tank rifle

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An anti-tank rifle is a rifle designed for shooting at tanks. The first anti-tank rifle was designed by Germany in World War I in response to first tanks. The large-caliber rifles were capable of penetrating early tanks' relatively thin armor and allowed infantry a better chance at stopping them. The anti-tank role soon required much more powerful weapons as armor became thicker on newer tanks. The weapon is the conceptual forbear to modern anti-tank weapons wielded by modern infantry, and both large-caliber sniper rifles and anti-material rifles owe a some part of their design heritage to it.