Odeon should be very aware of this, since we both live near the second largets city in Sweden and he lives even closer to it than I do. It's smaller than Washington, D.C., but there is about one car bomb a week and constantly criminals threatening and blackmailing restaurant owners etc. and using hand grenades and machine guns if they don't get their money...
One car bomb per week? This would make about 52 bombs every year, which is not true and you know it. However, in the last few weeks there have been 3-4 such incidents. Over the last year, perhaps some more.
Constant threats and blackmail against restaurant owners? Hand grenades and machine guns? There's been one restaurant owner in Göteborg who's been subjected to a lot of that, but which others do you know of? Do you have the relevant statistics handy?
Quite honestly, it would appear that we don't live near the same large city.
The police and the army have guns now, but does that stop the mafia and motorcycle gangs?
Sweden doesn't have mafia-like organizations to any significant extent, according to most sources (the justice department, a recent study, the police...). Organized crime in Sweden tends instead to be loosely knit networks that are very flexible in nature, meaning that there is no strict organization in place, as would be the case with the mafia. The motorcycle gangs you mention, for example, are not comparable with the mafia, but they can be a big problem where they occur.
According to a recent study, stopping organized crime is largely an organizational and judicial problem, not one one pertaining to guns. That part seems to work.