My impression is that the NRA is primarily supporting the gun manufacturers. If their mission was based on the owners of weapons, I believe they would take a more nuanced approach in their platform. I could not understand how they would not advocate for a more balanced policy that would actually be beneficial to the majority of gun owners. I believe gun owners would advocate for responsible ownership and that they would want their good name to be protected. I don't get the impression that the NRA does that.
As any lobbyist group, of course they are lobbying for that which they support, and receive money and donations (whether direct or indirect) from. It is kind of obvious and the point of this question is mildly irrelevant and baiting to the general public in an attempt to start some debate over something that isn't there.
The NRA is the hired hand of gun manufacturers. To think otherwise is awfully naive. They lobby for fewer laws, fewer regulations, and to relax the laws that are already on the books. It's absurd to think the gun manufacturers aren't reaping the rewards of all that lobbying and pushing. The NRA and the gun manufacturers are thick as thieves.
Brady center for violence prevention estimates what NRA received $39MM from gun manufacturers since 2005. While it might sound like a lot NRA collected over a $1 Billion in just membership fees in that time. It's total revenues are over $200-$220 millions a year and majority of it is membership dues and services.
With gun manufacturers contributing about 2% to the pie and having 4 out of 80 people on board NRA only cares about members. It's called capitalism, baby.
The NRA support a certain lifestyle, preserving hunting traditions that go back to the formation of the United States. They are also fighting to advocate for a system of checks and balances on government power over individuals. The notion that they are lobbying simply to receive money from gun manufacturers is an insufficient to generalization.