This is an interesting look at non-compliance with gun restrictions around the world. Some of the numbers are impressive; it is thought that only 20% of the guns in Australia are legally owned. Europe is not much different.
http://reason.com/archives/2012/12/22/gun-restrictions-have-always-bred-defian
http://reason.com/archives/2012/12/22/gun-restrictions-have-always-bred-defian