In the aftermath of the attempted murder of Rep. Gabrielle Giffords earlier this month, lawmakers on Capitol Hill have proposed a cluster of gun control measures ranging from a ban to knowingly carrying a firearm within 1,000 feet of certain high-profile government officials to a proposal to allow members of Congress to carry firearms in the U.S. Capitol. Rep. Carolyn McCarthy formally introduced her own bill on the House floor Tuesday that would ban high-capacity ammunition clips like the one Jared Loughner used to gun down 19 individuals in the Tucson shooting Jan. 8. McCarthy, who is regarded as one...