HOUSTON, TX - MAY 04: Attendees line up to enter the 2013 NRA Annual Meeting and Exhibits at the George R. Brown Convention Center on May 4, 2013 in Houston, Texas. More than 70,000 peope are expected to attend the NRA's 3-day annual meeting that features nearly 550 exhibitors, gun trade show and a political rally. The Show runs from May 3-5. (Photo by Justin Sullivan/Getty Images)