Fearing that the surveillance efforts of the National Security Agency could be used as a “backdoor” to construct a national gun registry, leaders of the National Rifle Association plan to press members of Congress in the coming weeks to block the controversial program, NBC News reported. “We will be up there and we will be making our feelings known,” David Keene, a member of the NRA’s executive board who served until this spring as the group’s president, told NBC News. “Our members are concerned about this. This metadata can be used to construct a list” of every gun owner.