Laws on gun control are as tough if not tougher in most European countries as they are in the UK. The problem is that you can buy a gun in a country with lax laws then drive to another without any checks.Ah, I hadn't realised you were in/talking about Europe, and yes, it is a different scenario there as Charlie Hebdo, Bataclan etc testify. Thankfully the UK being an island makes it a heck of a lot harder and more expensive to get the things in.
Weapons such as kalashnikovs tend to be sourced in the ex-communist states and, in just about every country, are banned.
Here's a list detailing gun ownership per country: https://en.wikipedia.org/wiki/Estimated_number_of_guns_per_capita_by_country.