What explains patterns of state formation in Africa? While the development of centralized states across the continent is conventionally assumed to have been constrained by geography and demography, we argue that state-building strategies were reshaped by access to modern military technology in the nineteenth century. We examine the processes of state formation through the case of Ethiopia under Menelik II to show that increased access to firearms facilitated a more aggressive and expansive approach to territorial consolidation. Using an original dataset of georeferenced state garrisons and historical polities, we find that the introduction of firearms allowed Ethiopia to expand state boundaries, secure valuable territories, and centralize authority in ways that are more consistent with bellicist understandings of state formation. The findings suggest that African state-building dynamics were more context-dependent than previously understood, necessitating a re-evaluation of the theoretical frameworks applied to the region.