Half of all guns in the United States are owned by people making incomes in the six figures, and much of the working class that does own guns are current or former military and police. There have been multiple studies on this through the few places that can self-sustain collecting this data (like the Harvard Injury Control Research Center).
Guns are expensive and maintaining the hobby is also extremely expensive, so of course people with more money have more tied into it. The NRA itself has membership dues only make up half its income anymore, with their private income sources and individual donations on the rise.
