Washington. Key gun-control legislation will be introduced Thursday by Senator Feinstein, an influential lawmaker and a leading advocate of gun control, will be joined by an array of congressional co-sponsors when she announces the details of the bill — which she has titled "The Assault Weapons Ban of 2013" — that is expected to specify what kind of military-style assault weapons would be covered by the ban, as well as define the kinds of high-capacity ammunition magazines that also would be outlawed.
President Obama also has endorsed those aims.
The 1994 ban on assault weapons authored by Senator Feinstein outlawed a specific list of rifles and stipulated that any such weapon would be banned if it had a detachable magazine plus two military-style features such as a pistol grip, a flash suppressor, a bayonet lug or grenade launcher.
Critics of the ban have said it was ineffective because gun companies simply re-engineered weapons to get around its requirements.
The new legislation to be introduced Thursday also will ban specific weapons but it will be different from the original law, which expired in 2004, sources familiar with the measure said.
The new ban will cover any weapon with a detachable magazine and a single military-style feature. "A one-feature test captures more assault weapons and makes it harder for the gun industry to evade the law by modifying a banned weapon," the San Francisco-based Law Centre to Prevent Gun Violence said in an assault weapons policy summary last year.
The Newtown backdrop for the Feinstein bill will be emphasised Thursday when she is joined by Connecticut senators Richard Blumenthal and Chris Murphy, as well as Representative Elizabeth Esty, whose district includes Newtown. Twenty kindergarten and first grade students and six staff members at the Sandy Hook Elementary School were killed with an assault weapon during the shooting rampage by Adam Lanza, who then killed himself.
Mr Blumenthal said the new bill "will be a more stringent measure than the assault weapon ban that existed from 1994 to 2004." He said a ban on assault weapons and high-capacity magazines will work in concert with school security enhancement and mental health reform.
"This measure is a significant first step as part of a comprehensive program," Mr Blumenthal said.
Ms Esty is expected to co-sponsor the House version of the Feinstein bill that will be introduced there by New York Democrat Rep. Carolyn McCarthy, another leading congressional advocate of gun control laws. Ms McCarthy's husband was killed and her son gravely injured in a 1993 shooting in New York.
At a hearing of the Gun Violence Prevent Task Force on Wednesday, Ms Esty praised testimony from a witness who said the first responders to the Sandy Hook school shootings will never be the same because of the trauma they suffered.
The witness, David Chipman, a 25-year veteran of the Bureau of Alcohol, Tobacco, Firearms and Explosives, recalled his work at the 1995 Oklahoma City bombing that killed 168 people.
"I was never the same" after that, he said. "It is likely that first responders from Newtown will never be the same. As we support the families who lost their loved ones in Connecticut, don't forget the first responders. They need your help."
The Newtown shootings have fuelled growing public sentiment in favour of tougher gun rules. A New York Times/CBSNews poll reported earlier this month that 54 percent of the American public favours stricter gun control laws, up from 39 percent last April.
The Feinstein bill will join other gun-control measures introduced this week, including legislation that would:
*Close the "gun show loophole" and require background checks for all firearms purchases. Federal law already mandates that gun buyers doing business with licensed firearms dealers must pass a federal background check before completing their purchases. However, the law has not such requirement for informal transactions, such as those conducted by private individuals, such as attendees at gunshows. This bill introduced by Senator Frank Lautenberg, Democrat of New Jersey, would change that.
"Criminals, terrorists, the mentally ill and other dangerous people shouldn't be able to walk into a gun show and walk out with guns and assault weapons, no questions asked," Senator Lautenberg said in a statement. "Closing the gun show loophole is a simple step that we can take to increase gun safety and prevent dangerous weapons from getting into the wrong hands." His bill would also ban high-capacity ammunition magazines holding more than 10 rounds.
*Beef-up the law prohibiting straw purchases of guns, transactions in which someone buys a gun for someone else who is barred from getting one on their own. Co-sponsored by Senator Patrick Leahy, Democrat of Vermont, chairman of the Senate Judiciary Committee, and Senator Richard J. Durbin, Democrat of Illinois, the bill establishes tough penalties for people who purchase guns intending to transfer them to someone else.
New York Times News Service