With the advent of guns that can be made of stock parts and a 3D printer the question should be asked: “What can be done to prevent anyone that wants one from getting a gun?”
The answer is simply put, nothing. This does not mean that I am a supporter of gun rights as they currently exist, but at the same time, I recognize a reality in which guns are plentiful and easy to acquire currently, and with the ability to print key parts of guns, this will only get easier.
There is no way to conceivably restrict either 3D printing technology (it is too useful, easy to recreate, and multi-purposed) nor the files that can be given to the printer to create the pieces given the raw materials. The MPAA has been fighting a similar battle for years, and their problem is comparably well defined. They know exactly what content they are looking for. With the state of technology today, there are many many distinct ways to create designs for these parts, they can be hosted in many formats, in ways that would be difficult to determine that they were all the same blueprint algorithmically (if the language that is used to create the blueprints for the printer is sufficiently complex, it could easily be impossible (this would be the case if the language was c++ for example)).
Since the technology side cannot be conceivably regulated, another thought would be to regulate the raw materials that would go into the gun pieces. Unfortunately, this too is impossible, as all it takes is plastic, and some simple metal pieces available at many hardware stores.
The question then becomes, “How can we prevent murder from being commonplace?” I believe that the answer lies in a fundamental misunderstanding of how guns kill people. According to the CDC, 31,672 people were killed by firearms in 2010. While this number may seem high, for a sense of perspective, more people were killed in car accidents. Additionally, more than half of the people that are killed by firearms pulled the trigger themselves. While this is very sad, this is not going to influence the incidence of murder by firearm. So we are really more concerned about the other 50% of people that were the victim of a shooting, accident, and the like.
Considering that in 2010 2,468,435 people died of all causes, one has to wonder whether our priorities are in order. Deaths by firearm excluding suicide accounted for approximately .64% of all deaths, and while these deaths are sad, in the scheme of things, this is not a large impact on society.
As terrible as it may sound, the same thing can be said of mass shootings. While they are tragic, the fact that a few tens of people were killed by a lone individual on the same day is not significant in terms of the death rates. It may make for many consecutive news broadcasts, but they don’t kill many people as a percentage of pretty much any other cause of death.
The government is attempting to regulate something that in the near future (or even today) will be impossible. While I appreciate the effort to solve the problem of mass shootings (and regular homicides by gun), the country has far far bigger problems. Perhaps we should stop worrying so much about gun control and focus on those.
While it might not be possible to prevent people from getting guns, it has been proposed by the NRA and others that a possible solution would be to have guards everywhere, this is both impractical and useless. The vast majority of homicides take place between people that know each other well. Unless someone is proposing that guards should be placed everywhere (20% of the homicides are between family members) there is nothing that can be done. Additionally, having guards brings with it its own problems (can a guard shoot in time, or will it only be reactive, in which case in most scenarios it is too late anyway, or considering the accuracy of the NYPD what if the guards kill more people than the murderer ever would).