I just read an article on Propublica.org that I thought you should read. This article goes into detail of how numerous mass shootings over the years in America do very little to change state gun laws. The article lists the shootings starting with the Virginia Tech shootings that killed numerous students. The list has mass shootings from Texas, Alabama, Colorado and New Mexico and each time law makers try to enact new laws but it is very difficult to do so.
Read the full article here:
Mass Shootings Do Little to Change State Gun Laws – ProPublica