Gun owners have filed petitions to block Maryland's pioneering ban on sales of cheap handguns and to force a public vote on the gun control law in November. Fred Griisser, chairman of the Maryland Committee Against the Gun Ban, submitted petitions Tuesday to the secretary of state that he said contained signatures of more than 22,000 voters. The committee will need 33,044 valid signatures by the end of June to force the law to referendum. Griisser said his group believes the law has the potential to ban all handguns. The law allows the state to ban guns that are cheaply made of poor quality materials and are so inaccurate that they can't be used for sporting purposes or defense. It also bans those that can't be detected by metal detectors.