Whoever is unbalanced enough to kill 30+ people, will find a way to do that. Taking the guns from folks that have every right to own them will not prevent this type of thing from happening. As I said before, one can kill large amounts of people with a couple of sacks of fertilizer. Would we then ban fertilizer? The logic is absurd.
Here is another bit of data I would like to see response to.
In 1998, a study conducted jointly by statisticians from the U.S. Department of Justice and the University of Cambridge in England found that most crime is now worse in England than in the United States. * "You are more likely to be mugged in England than in the United States," stated the Reuters news agency in summarizing the study. "The rate of robbery is now 1.4 times higher in England and Wales than in the United States, and the British burglary rate is nearly double America's."6 The murder rate in the United States is reportedly higher than in England, but according to the DOJ study, "the difference between the [murder rates in the] two countries has narrowed over the past 16 years."7 * The United Nations confirmed these results in 2000 when it reported that the crime rate in England is higher than the crime rates of 16 other industrialized nations, including the United States.8
If I thought that law abiding citizens giving up their right to own firearms would have any positive measurable effect on violent crime I would support it. The evidence just doesn't support that.