The earlier comment is conflating general Swiss firearms ownership with the service-weapon take home system in use with Swiss military conscripts.
Swiss gun owners are allowed to buy, own, and use ammunition. They may also use a privately-owned firearm in self-defense situationally, but the legal justification for use of deadly force in Switzerland will obviously be more stringent than it would be in the United States.
> They are not allowed to possess ammunition unless in special militias. Any ammunition bought or issued at ranges cannot be taken off premises.
So potentially yes, but only if you mean using the gun as a club.