FILE -- In this Aug. 15, 2012 file photo, three variations of the AR-15 assault rifle are displayed at the California Department of Justice in Sacramento, Calif. While the guns look similar, the bottom version is illegal in California because of its quick reload capabilities. Omar Mateen used an AR-15 that he purchased legally when he killed 49 people in an Orlando nightclub over the weekend President Barack Obama and other gun control advocates have repeatedly called for reinstating a federal ban on semi-automatic assault weapons that expired in 2004, but have been thwarted by Republicans in Congress. (AP Photo/Rich Pedroncelli,file)
{}