The current gun control debate is basically nothing but political opportunism from the left. It is tragic when evil, demented people do horrific acts such as the massacre that took place in Sandy Hook. It disgusts me that the president and others have used this as the jumping point to push their agenda for stricter gun controls. As horrific as these events are, good policy does not come from emotion but from analysis of evidence.
Nothing that has been proposed will prevent the next nutcase from appearing. Crazy people and criminals, especially those that are intent on murdering and ultimately killing themselves. Magazine size only matters if there is return fire. AR's, despite media description as "killing machines" function the same as any other semi-auto rifle. The caliber is lower than several others as well, though the media will never say that.
Furthermore, murder and violent crimes are not increasing nor are homicides. They are down significantly from the early 1990's though gun ownership has increased significantly. Don't believe me? Take a look at the FBI data. Pick a few years and see. http://www.fbi.gov/stats-services/crimestats