Clive,
In the last ten years Australia, England, and Canada have all increased the restrictions on owning firearms. Over that time violent crime (i.e. rapes, murder, hot burgleries, etc.) have increased in all those countries while we have seen a decrease over that same period in America. What has changed in the U.S. that could account for this? States have made it easier to obtain weapons permits and concealed carry permits. If you are interested in seeing the numbers on my ascertations as well as the refutation of "facts everyone knows are true about guns" check out this website.
http://gunfacts.info/