While self-defence with a gun is big no-no in Finland, there are some cases where the court has freed the person using a weapon for self-defence.
One case was where an intruder (broke in to the victims apartment) was stabbed with a decoration-sword. And the victim was freed in court because he was in imminent fear of life.

Another one where the intruder tried to climb in through a window above the door and was shot dead by the apartment owner. Here again the apartment owner was freed in court.