The Dumdum Arsenal was a British military facility located near the town of Dum Dum in modern West Bengal, India.
The arsenal was at the centre of the Indian Rebellion of 1857, caused in part by rumours that the paper cartridges for their muzzle-loading rifles, which they were expected to bite open, were greased with pig lard (a problem for Muslims) or cow fat (a problem for Hindus).
It was at this arsenal that Captain Neville Bertie-Clay developed the Mark IV cartridge, the so-called "Dum-dum bullet", a soft-point bullet, and a hollow point version designed to mushroom on striking. This was one of the first series of expanding bullets for military use. They were later banned in warfare by the Hague Convention as being "too inhumane."
On 7 December 1908, a serious, accidental explosion occurred at the Dum-Dum arsenal, resulting in the death or serious injury to about 50 native workmen.