I hate to say it but it has way more to do with us Americans just being more violent than Australians (and most other people) in general than it does with the gun culture (which I'm proud to be a part of by the way). The mass shootings get all the attention but the fact is that violent crimes committed with guns only make a small percentage of violent crime overall. Also violent crime statistics didn't change much in Australia after gun control was implemented. Also, when was the last time there was a mass shooting in Switzerland? All Swiss males are conscripted when they reach the age of majority and are expected to keep their assault rifles (which are higher quality than those issued by most armies) in their homes for the duration of their service.

So I'm thinking it has far more to do with the culture in general. What taking away guns does do, on the other hand, is leave the general population far more at the mercy of their government. Although if all guns disappear it wouldn't do much to effect the balance of power.