"Congress has debated the efficacy and constitutionality of federal regulation of firearms and ammunition, with strong advocates arguing for and against greater gun control. In the wake of the July 20, 2012, Aurora, CO, theater mass shooting, in which 12 people were shot to death and 58 wounded (7 of them critically) by a lone gunman, it is likely that there will be calls in the 112th Congress to reconsider a 1994 ban on semiautomatic assault weapons and large capacity ammunition feeding devices that expired in September 2004. There were similar calls to ban such feeding devices (see S. 436/H.R. 1781) following the January 8, 2011, Tucson, AZ, mass shooting, in which 6 people were killed and 14 wounded, including Representative Gabrielle Giffords, who was grievously wounded. […] This report also includes discussion of other salient and recurring gun control issues that have generated past or current congressional interest. Those issues include (1) screening firearms background check applicants against terrorist watch lists, (2) combating gun trafficking and straw purchases, (3) reforming the regulation of federally licensed gun dealers, (4) requiring background checks for private firearms transfers at gun shows, (5) more-strictly regulating certain firearms previously defined in statute as 'semiautomatic assault weapons,' and (6) banning or requiring the registration of certain long-range .50 caliber rifles, which are commonly referred to as 'sniper' rifles. To set these and other emerging issues in context, this report provides basic firearms-related statistics, an overview of federal firearms law, and a summary of legislative action in the 111th and 112th Congresses."
CRS Report for Congress, RL32842