Susan,
The Swiss have a culture of military service requiring most citzens to spend time in service and when they are done they take their rifle and other gear home to always be ready to defend Switzerland.
In WWI Hitler did not invade Switzerland mainly because of the armed and trained population. The right to own guns also kept Japan from invading the US in WWII. Owning guns scares your enemies and makes the think twice.

In WWII the Swiss had Schmidt Rubin K-31 rifles; a straight pull bolt action, now they get Sig SG 550's.
It is fully auto but not an anti-aircraft gun.