Swiss also have several classes of licencing requirements that must be regularly renewed. Limits on what types of guns and how much ammo you can buy and all their weapons must be registered at their local police station. Most citizens are not allowed to store ammo for their military issued firearm.
Over 40,000,000 Americans suffer from some form of mental illness. Some of them access to medical care, but all of them can buy guns thanks to Trump and the NRA.
http://fortune.com/2018/02/15/trump-shooting-mental-illness/
Trump Undid Obama Rule That Added Mentally Ill People to Gun Check Register