From everything I've seen it's almost completely unrelated to the abundance of firearms and mandatory conscription. Gun control is actually so strict that pro-gun Americans would consider it oppressive, and most Finns I've talked to have thought of the military service as being educationally helpful and not at all an affront to freedom.

I noticed a good percentage of cases involve family members (especially ones involving women, which makes sense), and not only a high incidence of alcohol but also of drunk driving.