Mass shootings are always tragic. Often they are accompanied by calls for tighter gun control. These usually come from people who were always against gun ownership like New York Mayor Michael Bloomberg.
The biggest argument against tighter gun controls is statistics. Gun violence has been dropping annually for decades. At the same time, gun ownership has been growing. Obviously this means that more guns does not equal higher gun violence. Similarly, crime rates between states with tight and loose gun control does not argue in favor of tighter regulations. When Florida allowed concealed carry experts predicted that it would mean an increase in gun deaths. The opposite happened. The same has been repeated across the country as concealed carry has become common.
So, guns and gun ownership do not automatically cause violence and death.
Mass killings are a special case. They happen too often but do they justify tighter gun controls? Let's put it into perspective. Just a few days after the shooting a truck full of people blew a tire and slammed into a tree. At least 13 were killed. Others are in life-threatening condition. Having this many people in a truck must have been illegal so using the gun control argument, we need to put tight controls on owning and operating trucks.
This sounds silly but there are more guns in the US than pickup trucks but pickups kill a lot of people.
The Aurora shooter used a high-capacity magazine. The Giffords shooter also used one. Should these be outlawed? A friend who is a shooter tells me that these make a handgun heavy and difficult to aim. They are also prone to jamming which happened to the Aurora shooter. Forcing shooters to use more reliable magazines might be a bad idea.
The real question is if limiting guns would actually stop crazed killers? In the Aurora shooting the alleged shooter filled his apartment with explosive devices so he was capable of alternate methods of creating mayhem.
The tragedy at Columbine is instructive. Most people are not aware of the killers' actual plans. They planted a bomb in the lunch room that was set to explode a few minutes after noon. They had previously done headcounts and figured that this is when the lunchroom had the most people. Their plan was to detonate their bomb in the middle of over 1,000 people. They also hoped to collapse the ceiling, killing or injuring people in the library above. The guns and pipe bombs were to be used on the survivors. When their bomb failed to go off they started shooting people on their way to the lunchroom where they attempted to manually explode their bomb. When it became obvious that the bomb was not going to go off they killed themselves.
Had things gone as planned the body count would have been an order of magnitude higher.
In their early stages of planning they had discussed hijacking an airplane and flying it into a high-rise.
The two worst acts of domestic terrorism (9/11 and Oklahoma City) did not involve guns. Similarly, the worst school killing happened early in the 20th century when a janitor caused a boiler to overheat and explode.
The point is that guns are tools. Other means of killing exist and are easily available. Worse, some of them are more effective.