Another issue is that there is not much evidence showing that gun control even decreases crime rates. But upon further research, one can find that it is not always about legal gun availability rather than illegally obtaining guns.
What I'm saying is that these are simple things that need to be taken into consideration when registering someone to hold a potential weapon to kill a person or persons.
All in all, the threat that guns bring will always be around, mass shootings will always be there. Gun control will not eliminate crimes or homicides, but I do believe that with the fits laws and rules it could decrease these rates significantly.