RICHMOND, Va. (AP) _ Democrat Sen. Mark Warner is getting some last-minute help from a group founded by former U.S. Rep. Gabby Giffords and retired astronaut Mark Kelly that wants to expand background checks on gun purchases. Americans for Responsible Solutions filed reports Thursday showing it spent $41,000 on radio advertising aimed at helping Warner win re-election. Giffords was shot in the head during a January 2011 shooting that killed six and left 13 injured. Warner has said he supports gun rights but also supports expanding background checks. The National Rifle Association has endorsed GOP challenger Ed Gillespie. Gillespie has also benefited from recent small-dollar independent spending by Americans for Prosperity _an organization backed by billionaire brothers Charles and David Koch _ and the anti-abortion National Right to Life Victory Fund.