Having said that, there is no need for these fucking AK-47's, AR-15's and others with high capacity, rapid reload magazines for any purpose. No, banning them won't stop someone from using a 6 shot revolver to kill but until we solve the root cause, let's try to limit the amount of damage these freaks can do. If the assault weapons ban was reinstated, I honestly believe it will reduce the frequency that these types of guns are used in crimes like this. If all it does is stop one mass shooting, or result in 10 dead instead of 30, it is worth it. Not a solution, but it is a step.
Statistics from mass murders from 1982-2012 show that assault type weapons were used 35 times, shotguns were used 19 times, revolvers 20 times, and handguns 68 times.
If you truly believe that assault weapons need to be banned, then you should really be going after handguns. Assault weapons aren't the problem. Outside of target shooting, hunting, or mass murders, they aren't practical. Semi-Automatic clip-fed handguns are more of a danger to people in my opinion than AR-15's and AK-47's. If you really want to change gun laws that would have the biggest impact on how many people die each year in the US, we should put restrictions on semi-auto handguns first. Statistically speaking, more people are killed with semi-auto handguns than with any other type of weapon.
Here is a really good article from an independent researcher regarding firearms and statistics: Doing The Math On Guns | Neon Tommy
Again, I still think the issue is more than firearms. 75% of the mass murderers in the last 30 years had a diagnosed mental health issue prior to their killing sprees. Why these people weren't kept in check by family or by more thorough background checks is beyond me.