The NRA with 4 million members claims to speak for 100 million gun owners.
http://en.wikipedia.org/wiki/National_Rifle_AssociationThe NRA is designated as a 501(c)(3) and a 501(c)(4) organization, which allows it to operate both as a charity and to participate in political campaigns and lobbying.
http://www.theatlantic.com/business/archive/2012/12/whom-does-the-nra-really-speak-for/266373/WHO DOES THE NRA REALLY SPEAK FOR
IT SPEAKS FOR GUN MAKERS
But membership fees don't pay the NRA's bills alone. In recent years, the group has become more aggressive about seeking donations, both from individuals and corporations, and that in turn has led it to become more deeply entwined with the gun industry. In 2010, it received $71 million in contributions, up from $46.3 million in 2004. Some of that money came from small-time donors, who've received a barrage of fundraising appeals warning of President Obama's imminent plot to gut the Second Amendment and confiscate Americans' firearms. But around 2005, the group began systematically reaching out to its richest members for bigger checks through its "Ring of Freedom" program, which also sought to corral corporate donors. Between then and 2011, the Violence Policy Center estimates that the firearms industry donated as much as $38.9 million to the NRA's coffers. The givers include 22 different gun makers, including famous names like Smith & Wesson, Beretta USA, SIGARMS, and Sturm, Ruger & Co. that also manufacture so-called assault weapons.