Movement-countermovement pairs develop in opposition to one another as they battle for position, influence, and survival in a shifting political and cultural context. While theoretical work on countermovements and the political context posits a rough symmetry between opposing movements, our analysis demonstrates significant asymmetries in the fight over gun policy in the United States. Drawing on news accounts, government records, public opinion polls, and organizational-capacity data for twenty-six gun control and twenty-nine gun rights groups, we show that both sides grow during policy fights and after focusing events, but the side with more stable revenue sustains growth longer. The gun rights movement’s financial advantages made it far less dependent on attention-grabbing moments. This imbalance reflects resource differences that affect each side’s capacity for responding to political opportunities and threats. Our findings highlight the need for more research on the implications of resource and power imbalances for effective organizing.