This interactive bar chart visualizes firearm background check data across U.S. states, showing stacked totals by gun type (handgun, long gun, other, and multiple) for a selected year. Users can filter by year and choose to display the top 10, top 25, or all states. Hovering over bars reveals detailed category tooltips, while hovering over the legend highlights a specific gun type. Built with D3 v7 and d3-rosetta, it uses scaleBand and scaleLinear for axes, transitions to animate opacity changes, and CSV-loaded data aggregated per state.