Out of curiosity I checked some of GundamFan's sources and a few of them source the same crime prevention research center. That organization was founded by a gun's rights advocate who may have accepted funding from the NRA, and the site itself has a huge right-wing slant. Some of his work is also considered "junk science"
http://crab.rutgers.edu/~goertzel/mythsofmurder.htm
Just to bring some more perspective.
EDIT: Additionally many of his articles cited are opinion pieces. One of them is by Ben Shapiro, who worked for Breitbart for one.