BRIDGEPORT, Conn. — Lawyers for the company that made the rifle used to kill 20 first-graders and six educators at Sandy Hook Elementary School are expected to ask a Connecticut judge to dismiss a wrongful-death lawsuit filed by families of some of the massacre victims.

Freedom Group, the Madison, N.C., parent company of AR-15 maker Bushmaster Firearms, is arguing it is protected by a 2005 federal law that shields gun manufacturers from most lawsuits over criminal use of their products.

Lawyers for the plaintiffs, who include the families of nine children and adults who died and a teacher who survived, say the lawsuit is permitted under an exception to the federal law that allows litigation against companies that know, or should know, that their weapons are likely to be used in a way that risks injury to others.

The victims’ attorneys say the lawsuit appears to be the first of its kind against a manufacturer to claim that exception.

Bridgeport Superior Court Judge Barbara Bellis is set to hear arguments today on Freedom Group’s motion to dismiss.

State police say the 20-year-old gunman, Adam Lanza, killed his victims with a Bushmaster XM15-E2S rifle, a model of the AR-15, on Dec. 14, 2012.