.... In issuing the regulations, senior officials said, the administration will have acted on all 23 executive actions that the president and Vice President Joseph R. Biden Jr. announced early this year to reduce gun crimes after the Newtown, Conn., school massacre. In planning those actions, the administration anticipated that gun control legislation would fail in Congress as pressure from the gun lobby proved longer-lasting than the national trauma over the killings of first graders and their caretakers last Dec. 14. ...