This is not possible. According to the Reuters story, the gunman did not have a license!
/sarc mode off
c.w.
He must have studied police commando operations, and knew the importance of forest type camouflage in a modern western city.
Socialist and conformist present day Scandinavia leaves no outlet for the Viking berserker genes some born there carry. The social pacifism means there are no seal team style of military units that could absorb and give these alpha males some useful outlet. Norwegian and Swedish U.N. peacekeeping military contributions are blue hats meals on wheels and not exciting enough for these dudes.
Sad, RIP.