Clayton E. Cramer first breaks down why new weapons bans are not the solution, and then gets to the real issue:
> If we are serious about reducing these relatively rare (less than 1 percent of U.S. murders are incidents of mass murder) but terrifying tragedies, we need to be looking at the root cause: untreated or inadequately treated mental illness. Focusing on the weapons may be good politics, but the experimental evidence suggests that it is bad public policy.
I strongly recommend you read the whole piece.