By Katie Kerwin McCrimmon As Adam Lanza fired 154 shots from a rifle, mowing down 20 first graders and six educators at Sandy Hook Elementary School, a group of gun control advocates and law enforcement officers happened to be meeting in Colorado to craft legislation to curb gun violence here. Rep. Rhonda Fields, D-Aurora, who lost her son to a 2005 shooting, and Rep. Beth McCann, D-Denver, a former prosecutor and Denver manager of safety, both attended the Dec. 15 meeting. The news from Newtown, Conn., was fresh and shocking. Heartbreaking updates came in spurts on phones. No one knew…