The dum-dum bullet was a British military bullet developed in India's Dum-Dum Arsenal and used on India's North West Frontier and in the Sudan in 1897 and 1898. It was a jacketed .303 cal. British bullet with the jacket nose left open to expose the lead core in the hope of increasing effectiveness. Found on http://www.probertencyclopaedia.com/browse/FD.HTM