Do you mean no one should have a shotgun licence?
If you have an imaginary population of 300 people 100 mentally ill ,100 criminals and 100 neither ill or criminals all with shotguns .At the end of each year there are 3 murders 1 by a mental 1 by a criminal and 1 by a person neither ill nor criminal .Oh my god these crimes must stop gun control is needed ,so mentally ill and criminals can no longer have guns ..now thank god there is just 1 gun murder a year, gun control works .the 1 murder a year is committed by the right sort of person .So to prevent the 1 murder a year the right sort of pe