Oddly enough, the ability for researched to understand this problem more has been essentially prohibited by government. In 2015, Congress quietly rejected an amendment to the 1996 Dickey Amendment that would have allowed the CDC to study the underlying causes of gun violence. It appears the gun lobby put pressure on congress to get the Dickey Amendment passed under claims that the CDC was engaging in propaganda and being used to bring on more gun control in America. The current study was conducted from research done in the 90s, as no new research is allowed.

The CDC is one government agency and they are only restricted from promoting gun control, don't be mislead. They actually do a lot of firearms research but they are just not allowed to make shit up to promote gun control as they were caught doing in the past.