A lower court threw out their case a year ago.
A lawyer for families who lost loved ones in the 2012 Sandy Hook school shooting told Connecticut's highest court on Tuesday that Remington Outdoor Co [FREDM.UL] should be held responsible because its military-themed marketing was created to appeal to young men like killer Adam Lanza.
"The weapon he needed for his mission was never in doubt", the families' attorney Josh Koskoff said.
The Protection of Lawful Commerce in Arms Act prevents a "qualified civil liability action" from being brought against firearm and ammunition manufacturers or sellers in both federal or state court.
20 children and six educators were killed in the shooting.
"Remington may never have known Adam Lanza but they had been courting him for years", Koskoff said. "He idolized the military and Remington advertised the AR-15 as the weapon used by Army Rangers". Negligent entrustment is specifically excepted from the 2005 gun maker shield laws.
David Studdert, a Stanford law professor, said on Monday he thought negligent entrustment was a tough argument for the families to make because it has traditionally involved someone having direct knowledge that another person poses a risk. Several groups including the National Rifle Association and emergency room doctors submitted briefs to the court.
The lawsuit, which was filed in 2015, was dismissed in 2016 by a lower court.
The plaintiffs argued the law does not protect Remington because it marketed the rifle "not for sport or for target shooting or self-defense" but "for exactly what it was", Koskoff said.
"Soldiers go through more than 100 hours of extensive training and they're carefully screened for mental illness before being issued the weapon", he said. "No matter how much we wished those children and teachers were still alive, the law needs to be applied", Vogts told justices.
But moves to even modestly tighten gun control laws floundered and a lawsuit brought by some families of the victims against the manufacturers of the semi-automatic gun used in the crime was thrown out by a judge past year.
Assault weapons were banned in CT after the Sandy Hook shooting. A federal ban on such weapons was passed in 2004 and expired a decade later.
He said and the other plaintiffs have "not lost one ounce of confidence in the justice of our case" and have the "utmost faith in the legal system to serve the people it's meant to protect".
He appeared at the hearing.
Ian Hockley, father of slain first-grader Dylan Hockley, said the rules and restrictions on assault rifles in the military should be applicable to the general public.
Lawyers for the defense have noted the gun was lawfully sold to and purchased by the shooter's mother, Nancy, before she was murdered by the shooter.