The law, passed quickly in the aftermath of December's mass shooting at the Sandy Hook Elementary School in Newtown, Conn., also extends the state's assault weapons ban. It specifically bans the Bushmaster AR-15, the weapon used by Adam Lanza to kill 20 children and six staff members.
The suit was filed Wednesday in federal court in Bridgeport, The Hartford Courant reported. It says the law, signed in April by Gov. Dannel Malloy, violates the Second Amendment.
"The act was rushed through the Legislature without thorough debate or meaningful public examination," the plaintiffs say in court papers. "The act irrationally bans pistols, rifles, shotguns, and magazines that are commonly used for lawful purposes by countless law-abiding citizens in Connecticut and throughout the United States."
Andrew Doba, a Malloy spokesman, said the state will defend the law. He said the lawsuit was expected.