I'm not trying to butress pbjosh's arguments but, you have to look at (and control for) a lot more factors than just gun regulations before you can say that restricting gun ownership is the best or most appropriate method. For example, both of those countries have better mental health care availability than the U.S. (even on a simple # of psychiatrists per 100K people basis). Or for another example, economic distribution in those countries is quite a bit flatter than the U.S. This gets to the point that Cockerpunk has been making- we need more data.
In spite of all that, it would appear (again lacking direct, official numbers) that Sweden's policies haven't been doing so hot in regards to reducing homicides committed with a firearm (Sweden's Public Television investigation):