Beccaria's thoughts are still valid today. No citizen over here can defend himself against an armed attack. Anybody who wants a gun can obtain it illegally - you only have to know the right places where to ask.
In Switzerland they have the concept of a nation in arms. Every young man having served his "boot school" in the army takes his rifle with him and keeps it at home in a cupboard for further use during training programs; you often find three generations of rifles in a house. But you never hear of crimes committed with such weapons.
And never forget: Weapons are tools and must be handled with responsibility - but they still stay tools. The wish to kill and maim doesn't come out of a weaponry, it comes out of the heart of man.