Remington Arms will pay $73 million to the families of five children and four adults killed in the Sandy Hook Elementary School massacre, the families said Tuesday, marking the first time a gun-maker has agreed to a major settlement over a mass shooting in the United States.

Twenty students and six adults were killed on Dec. 14, 2012, in Newtown, Connecticut, by gunman Adam Lanza, who used a Remington Bushmaster AR-15 rifle to shoot his way into the Sandy Hook Elementary School after killing his mother at home.

Remington Arms will pay $73 million to the families and release all discovery and disposition material to the public. The settlement will be paid through insurance policies, lawyers for the families said in a statement.