Puzzled by why anyone would downvote a pure question. Wide distribution of guns is an obvious commonality between the US and Switzerland; if that's offensive observation please let me know why!

It's a very common misconception that it's legal to own/keep a gun (after having done military service) but not being able to get/keep ammunition.

According to this video you can't keep preciously-lent ammunition from the military. But you can for sure buy your own.

https://youtu.be/L00Pajw4NoY

As to why people don't use it or aren't scared, I guess they just aren't as wild...

Probably because only the US has the kind of gun violence that you're wondering about. I don't think in Europe, the idea that someone is going to come after you with a gun because you pissed them off generally hits the radar.

Someone may find the question offensive because of that.

Fair enough.