"Virginia Tech. Gabby Giffords. Now Aurora, Colo. The names and places are linked by tragedy, death and the Glock semiautomatic handgun. The young men who carried out these mass shootings — and analysis says such killers are almost always male and most often young — all counted at least one of these versatile, easy-to-fire pistols in their arsenals.... Like other mass shootings, Friday’s attack sparked calls for more gun control."