Sen. Rand Paul, the tea party favorite and possible 2016 presidential candidate, is raising money for a conservative gun rights group that’s targeting fellow Republicans, including House Majority Leader Eric Cantor. And when one congressman complained, the message from Paul’s camp was: too bad. The Kentucky Republican has lent his name to fundraising pitches for the National Association for Gun Rights, a group that says the National Rifle Association is too willing to compromise on gun rights. The group has blitzed the districts of Virginia Republicans Cantor and Rep. Scott Rigell with $50,000 worth of TV and radio ads accusing...