In 1899, the first Hague Conference outlawed the military use of expanding small arms ammunitions, also known as dum-dum bullets. This chapter contextualises this moment of weapons regulation, connecting it to the controversies that evolved around smokeless gunpowder ammunitions during the 1890s, beginning with so-called ‘humanitarian’ full-metal jacket bullets that created smaller and cleaner wounds than the previous generation of large-calibre ‘man-stopping’ bullets. When the British military decided to modify their full-metal jacket bullets so that they would wound and kill their adversaries more effectively, media outrage ensued, which was fuelled by evocative newspaper reporting and graphic reproductions of dum-dum wounds. This media frenzy helped to justify the dum-dum ban at The Hague. The chapter also describes the public diplomacy strategies employed by the British government in justifying their use of these bullets, particularly against non-European and colonial adversaries. Altogether, the chapter shows how quickly the idea that a dum-dum bullet was a peculiarly transgressive weapon was normalised.