I worked in Switzerland for a year 30 years ago, and have visited a few times recently, It has really really changed.
In the western world, Switzerland and Australia are about tied for the largest proportion of immigrants in their populations.
On raw numbers Switzerland is low for number of migrants, but well above German, UK in terms of migrants as a proportion of population
On the other side of the coin, a lot of immigrants into Switzerland are from Italy and France. But those are themselves countries with more gun control.
I'd like to see the demographics by gender and age breakdown on this vote or the pre-vote polling.