Joshua Koskoff represents 10 Newtown families suing Remington, the manufacturer of the AR-15 used to kill 20 children and six adults three and a half years ago.
The AR-15 worked exactly as it was designed to do.
The families claim Remington and its distributor were "negligent" in allowing the gun to get into the hands of a mentally-ill gunman. Defense lawyer, Peter Berry says that's not true.
"Nancy Lanza never visited Sandy Hook Elementary School with a firearm -- it was her son who did," he said.
It's the latest challenge to the 2005 federal law that shields the gun industry from most lawsuits over the criminal use of firearms.
But the Newtown families say the way the military style weapon is marketed is the problem. They point to advertisements that use phrases like "consider your man card reissued".
Mark and Jackie Barden lost their seven-year-old son Daniel at Sandy Hook.
"They are not advertising these weapons for hunting, they are are not advertising these weapons for protection," Ms Barden said.
A week after, another gunman used a similar high-capacity military style rifle to kill 49 in an Orlando club. Georgetown law professor Heidi Feldman says the stakes are high in this case.
"The gun industry, I believe, is terribly afraid of being the next cigarette manufacturer," he said.