Thanks for bringing that up: the Swiss firearm-related murder rate is 10x that of the UK. In a country that overall not only has a much lower crime rate (as you rightly point out), but is generally proverbially peaceful.
(Examples: when my sister moved to Aigle in the south of Switzerland, she noticed that the flower shop had left some very valuable plants outside over the weekend. With price tags, so you knew which ones to take. She thought someone was obviously in trouble, but the owners left those plants outside very weekend. And yes, nobody locked their doors.
I was walking with a friend in Basel, and we saw a key taped to the gate of an apartment building. With a note reading "Only for the owner!!".)
Switzerland is an almost comically peaceful and safe place. Yet 10x the gun murder rate of the much less peaceful and safe UK (I lived in London for 3 years).
So how does this support the idea that having firearms widely available does not have a negative effect?