The US has a well-known loophole allowing people to buy guns without any check or registration by buying from a private citizen or at fairs.
Switzerland has no such exceptions. To acquire guns, you need to apply for a permit and register them. Inherit guns? Same. Go to a gun fair? The cops are actually there so you can get an express permit if you had already been giving a valid one that’s less than a year old.
Licensed dealers aren’t allowed to check anything: you bring the permit delivered by the police, they check that and your ID and have to file the registration on purchase.
In Switzerland, there is no legal framework for gun self-defense and it states so clearly on the permit: it’s a permit to buy a gun (and related gear like ammo), you can keep it at home, take it (strictly unloaded including mags) to the range or an armorer and that’s it. Carry permits are only for professionals.
Edit: Switzerland is actually more permissive in the type of weapons one can buy as long as one gets the right permits. Buying a fully automatic short-barrel rifle with a suppressor would be much easier and cheaper than in the US. The hassle would be finding a place to shoot it since taking a full-auto to a range requires an additional daily permit and the range to allow it.