The NRA is America's oldest Civil Rights organization.
The National Rifle Association started out a few years after the Civil War by two Union officers who discovered during the war that the troops couldn't shoot worth squat. The goal of the organization was to teach Americans how to shoot better.
And for about 100 years, it mainly was an organization dedicated to promoting the shooting sports, hunting, teaching people how to shoot safely, helping to train law enforcement, etc.
Then in the 1970s after the 1968 Gun Control Act severely curtailed our gun rights, the NRA had a change of management and they got active in defending our gun rights.
Since then, the NRA has continued its earlier mission, but devoted a lot of time and resources to fighting new gun control, often successfully, but sometimes not.
Many will say the NRA is so effective because of their money or because they get backing from the gun industry. Not true. The NRA gets it's power from their membership. Over 5 MILLION Americans are dues paying members or paid for expensive life memberships, and they often donate extra to help the cause. Those 5 Million NRA members care about this issue. They vote, they contact Congress, they mobilize to help friendly candidates and oust gun-grabbing candidates. That is the real source of the NRA's power.
You might say, only 5 Million members? That's not that much. Remember, this is 5 million members who are willing to pay annual dues of $25, $35, and now even $40 a year. In the USA there is only 1 other group with 5 million or more dues paying members, and that's the AARP, and that's because they give awesome discounts to members on many things.
Hope that helps!
NRA dues paying member for 35 years now.