The arms business is booming. Between 2014 and 2023, EU countries have increased their defense spending by more than half, reaching 632 billion euros annually, and the defence budget is to explode in 2025. With defense budgets surging globally, how can journalists effectively investigate the defense industry during this period of rapid growth? In recent years, two reporters from Investigate Europe have uncovered hidden aspects of the German Rheinmetall Group's operations, including its covert trade in ammunition factories. This workshop will share their insights and techniques, demonstrating how to investigate companies, employees, and trade flows in the defense sector. Participants will gain practical knowledge of investigative tools and strategies to uncover the concealed practices driving the arms industry's expansion.