13 mm bullet from a German anti-tank rifle, 1918.
The world's first anti-tank rifle was developed near the end of World War One (1914-1918) in 1918, it had an effective range of 500 metres. Bullets like this could penetrate over two centimetres of armour plate when fired at 100 metres.
NAM Accession Number
National Army Museum, London
National Army Museum, Battle gallery