Dick's Sporting Goods (DKS) said it's pulling some rifles from store shelves. And private equity firm Cerberus said it will sell its stake in Freedom Group, which owns the Bushmaster rifle brand and produced one of the weapons believed to have been used to kill 20 children and six adults at an elementary school in Newtown, Conn. If mutual funds and other large institutions follow Cerberus' lead and sell shares in firearms companies, gun makers