Guns and power go together. As in our own time, most forms of inequality in the global 19th century depended on a weapons gap. The unequal distribution of firearms helped determine power relations both between countries and within countries. Where did all those guns come from? And why did some have so many, and others so few? The Project on Arms Trade History [PATH] seeks to answer these questions by doing something unprecedented: quantifying the global arms trade between the end of the Napoleonic Wars and the outbreak of World War I. For the past several years, our team has been extracting data from customs reports issued by the globe's major arms-producing and arms-trading nations, and using it to populate a relational database. We are moving into the final stage of data entry, and hope to recruit a discovery team to help us solve problems and transition to data analysis. First, we need to develop and deploy stress tests so we can understand and address issues with data accuracy. Second, we face a variety of challenges on account of cross-source (in)compatibility: with differences in how countries recorded the arms trade. Third, we need a scalable solution to the problem of double counting that arises from tracking imports and exports (a gun exported from France to the U.S. is counted twice). Finally, we hope to end the semester with a preliminary front-end mock up enabling users to confidently interact with the database.