SAN ANTONIO, TEXAS - JUNE 17: Semi-automatic weapons for sale are on display at Texas Gun, one of the 6,700 gun dealers located near the 2,000 miles long U.S.-Mexico border. (Photo by Gilles Mingasson/Getty Images) DOVER, Del. - Democratic lawmakers in Delaware have introduced legislation outlawing the sale or possession of a wide variety of semiautomatic firearms and prohibiting anyone under age 21 from buying a firearm.