BOULDER, Colorado — Boulder’s newly enacted “assault weapons” ban is meeting with stiff resistance from its “gun-toting hippies,” staunch liberals who also happen to be devoted firearms owners. Only 342 “assault weapons,” or semiautomatic rifles, were certified by Boulder police before the Dec. 31 deadline, meaning there could be thousands of residents in the scenic university town of 107,000 in violation of the sweeping gun-control ordinance.