A Rockville gun store owner who said he would sell the nation’s first smart gun — even after a California gun store removed the weapon from its shelves to placate angry gun-rights activists — backed down late Thursday night after enduring a day of protests and death threats. Andy Raymond, the co-owner of Engage Armament, a store known for its custom assault rifles, had said earlier this week that offering the Armatix iP1 handgun was a “really tough decision” after what happened to the Oak Tree Gun Club near Los Angeles. Oak Tree was lambasted by gun owners and National...