Recent spree-killings and a controversial 2^nd Amendment Supreme Court ruling have re-directed criminological research toward the critical question of how best to prevent gun related fatalities. However, a recent National Academy of Science report raises methodological concerns about many of the most commonly cited and reviewed gun policy research designs, which re-introduces scientifically the question of whether any existing gun-intervention actually prevents fatalities. The present study adjusts for those concerns to then re-estimate the effects three of the most common gun interventions in the U.S. may exert on homicide rates and gun homicide rates in 20 major cities over a 36-year period. The results suggest that the Brady Law and one specific type of sentencing enhancement for gun crimes detectably reduce both outcomes, but that the others are ineffective. Policy implications and suggestions for future research are also discussed.