American anti-gun lobbyists yesterday said the outpouring of public outrage over a series of high-profile shootings could finally force lawmakers to implement long-sought restrictions on firearms. The balance had been tipped, they suggested, by a 16-year-old boy from an Indian reservation in Minnesota, who on Monday shot dead his grandfather, a veteran policeman, his grandfather's partner and seven people at a high school before killing himself. It followed the massacre on March 13 of seven worshippers at a Wisconsin church by a man who also shot himself and the courthouse shooting in Atlanta the previous day of a judge, customs officer and two other people, by a man standing trial for rape. Brady Campaign to Prevent Gun Violence co-director Chad Ramsey claimed the successive tragedies had started a groundswell of opposition to firearms that legislators could not ignore. 'People now see that the present situation is problematic,' Mr Ramsey said from Washington. 'Because of these tragedies, they're starting to sit up and take notice.' He described what he perceived as a lack of legislation on gun ownership in the United States as 'crazy', but said that lawmakers could no longer be oblivious to the problems. Lobbying for change was difficult because of the strength of the National Rifle Association, which had the backing of Congress. 'At Congress, we've made no progress whatsoever, largely due to the National Rifle Association being so successful in spreading mistruths and trying to paint itself a patriotic image and wrapping itself in the flag,' Mr Ramsey said. The pro-gun lobby claims the Second Amendment to the US Constitution gives citizens the right to carry guns. But Mr Ramsey and others alarmed by the number of Americans killed and injured by guns each year claim that the drafters of the law had state militias, not ordinary citizens, in mind. They accuse the association of seeking to expand the gun industry by making it easier for people to obtain weapons. National Rifle Association spokeswoman Kelly Hobbs rejected such suggestions. 'It is callous and shameful to politicise a tragedy such as the recent school shooting,' she charged. 'Unfortunately, groups like the Brady Campaign use tragedies as an opportunity to restrict the rights of law-abiding Americans to protect themselves and their families.' US gun ownership outstrips other developed countries by at least two to one. There are about 200 million guns in the US, almost one for every adult. At least 30,000 people die in shootings each year. George Washington University professor of psychology David Silber doubted the latest shootings were copycat in nature. He described the Minnesota teenager as apparently 'angry at the world', alienated and 'wanting to get back at everybody'. The courthouse killings were the act of an opportunist who had seized a gun when the chance arose, while revenge seemed to be the motive in the church shootings. Professor Silber compared the Minnesota Indian reservation shootings to that at a high school in Colorado in 1999, when two students shot dead 13 people and injured 21 others before killing themselves. They had also been loners, he explained. With much poverty on the reservation as a result of 40 per cent unemployment, and the boy's parents apparently having disowned him, emotions played high in his subsequent actions. 'His alienation and helplessness made him decide on the spur of the moment that he would do it,' the professor suggested. University of Minnesota professor of child psychology Esther Wattenberg agreed, saying that life on reservations was difficult. 'There are certain ways in which traumatic events in the life of a child are very intense for children on reservations,' she told The Christian Science Monitor. A study of one reservation revealed astonishingly high levels of family trauma, she said. There was also little access to mental health and drugs clinics.