In 1890, in the midst of an extended public debate on the right of women to work and the conditions of those who did, a small arms ammunition factory was built on the banks of the Maribyrnong River in Victoria. The Colonial Ammunition Company employed women almost exclusively from its establishment until the end of World War I. During this time, the workforce became the largest group of women workers engaged in the metal industries across Australia. This article will draw out their working experience by focusing on several key questions. Why were women employed? How was their experience and how were their methods of organisation shaped by gender? How did World War I impact on this experience? Exploring the answers to these particular questions draws out some of the key ways in which gender shaped the working lives of these women.