The thesis aims to understand how ghost AR-15 rifles, which have emerged as a weapon of choice in Latin America, challenge gun control practices at the international, regional, and local levels. It is referred to as a ghost because it is assembled with unregulated industrial parts of a rifle and an unmarked airsoft lower, rendering it untraceable. To trace a rifle without serial markings, its transnational itinerary had to be reconstructed using data from seizures of other ghost AR-15 rifles and their components, shedding light on dynamics that would have otherwise remained hidden. To achieve this, the biography of the object is used as an analytical strategy, with each seizure providing an opportunity to piece together different parts of the narrative of the fictional rifle X that challenges international, regional, and local control practices before ultimately reaching its destination in Rio de Janeiro. In these control practices, each weapon is framed as a unit with a life cycle, characterized by distinct and well-defined stages that imply opportunities for intervention to make them controllable throughout their journey. However, this process is not as linear as it is portrayed. These ghost rifles challenge these intervention opportunities, not only because of human error but also due to their modular design and the replaceability of the lower receiver—the sole traceable component. This undermines one of the fundamental principles of gun control architecture: traceability. Therefore, this work reflects on how the materiality of weapons interacts with and reshapes gun control practices.