Semi-automatic guns with detachable magazines are a unique threat to public safety, having been designed specifically to unleash bullets rapidly while reducing reloading time to seconds. Colorado lawmakers have a clear and compelling interest in limiting mass casualty events by banning the sale of these “assault weapons,” and House Bill 1292 would save lives. The bill, which has passed the Colorado House but now faces a tough road ahead in the Senate, defines “assault weapon” generally as a semi-automatic gun (both pistols and rifles) that has a detachable magazine and one other feature in a list of things designed to make the gun easier to wield in an active-shooter environment.