Denmark
In Denmark airguns can be owned by anyone over the age of 18. There are no restrictions regarding muzzle energy. As of June 2012, the laws change (with the consequence that some 600,000 Danes could be breaking the Firearms Laws), in that some air guns will require a license, or membership of a gun club to own them. This law is being contested by many parties.
Read more about this topic: Air Gun Laws