Indiana has really lax gun laws. Gun dealers are required to perform a very basic background search while a vendor can sell their “private collection” to anyone at a gun show without any background search whatsoever. So someone can buy an assault rifle at a Crown Point Indiana gun show without any background search, and drive an hour into Chicago, where assault rifles are banned. A 2015 study by the University of Chicago suggested that only 11% of guns involved in crimes in Chicago were purchased through federally licensed gun dealers, which require background searches. In 2014 the Chicago Police reported that roughly 60% of guns used and recovered from crime scenes between 2009 and 2013 were purchased outside of Illinois. Exact figures are hard to pin down but it is clear that the vast majority of guns making their way to the streets of Chicago are coming from outside of Illinois.