In response to several mass-casualty shootings in the United States, multiple legislative bodies have promoted or adopted laws that restrict the magazine capacity of firearms. The stated intent of these laws is to reduce the number of rounds a bad actor can fire in a mass-casualty situation. However, objectors argue that the laws not only are ineffective but could also cause an undue burden on the ability of law-abiding gun owners to protect themselves. Using agent-based simulation modeling, a home-invasion model including two-armed bad actors and a one-armed homeowner was created to test this hypothesis. The homeowner engaged the bad actors with different capacity magazines, and the survival rate was recorded and compared across the spectrum of capacities. This model showed that reducing the homeowner's magazine capacity resulted in an increased casualty rate for the homeowner.