New York City has some of the strictest gun laws in the US. Yet is is possible for anybody (regardless of gender, national origin, ethnicity, age or mental health issues) with $500 to purchase a gun illegally.
The guns are there for the buying. Mention your desire to make a purchase “on the street” and it usually takes about 2 to 3 days before someone will come through with what you want (or pretty close to it). During those 2 or 3 days the potential sellers are doing their own kind of a background check on the buyer. It’s all illegal and they don’t want repercussions. In some ways their checks are more thorough. They are not looking for the same kind of information but the information that they do get doesn’t rely on public records which due to privacy regulations are incomplete and lacking in pertinent detail.
The problem with state laws that do require background checks is that politically correct privacy laws get in the way.
In the case of the shooting in Virginia and more more recent horror in Tucson; both shooters had a history of threatening behavior that was on public record. Both shooters had previous contact with local police; again on public record. Both shooters bought guns legally even though they had histories of psychiatric problems with anger control issues.
It is not the lack of regulation with regard to guns; but the politically correct, over regulation when it comes to “privacy issues” that makes accurate oversight impossible.