"Jared Loughner, the 22-year-old accused in the Tucson shooting, has a petty criminal record, yet there’s no evidence that his background contained anything that would have prevented him from buying a handgun in Arizona, where limits on owning and carrying a gun are among the most permissive in the country, according to the Brady Campaign to Prevent Gun Violence, a gun-control advocacy group. Critics have focused on the extended magazine used in the shooting that would have been illegal until 2004 under the expired federal ban on assault weapons. The clip — still banned in some states, including Massachusetts — allegedly allowed Loughner to fire 33 rounds without reloading."