"Freedom is not a gift from government, freedom is a gift from God," Trump said.
Trump, the first sitting president to address the NRA since Ronald Reagan, delivered a fiery speech in which he recounted his election victory and early actions from his administration that are friendly to the gun rights group, and he promised there would be more to come.
"You came through big for me, and I am going to come through for you," Trump told thousands of members attending the NRA's annual convention. "The eight-year assault on your Second Amendment freedoms has come to a crashing end. You have a true friend and champion in the White House."
With his appearance here, Trump marked the coming 100-day milestone in much the same way he has governed in the early stages of his presidency: by appealing to his base. While his job approval numbers have been historically low for this point in his presidency, Trump's most enthusiastic supporters are standing by him, polls show.
The NRA claims 5 million members, including many white rural voters, a demographic that helped tip the electoral college in Trump's favor.
The association played a powerful role in Trump's election, providing critical support in battleground states. It spent more on behalf of Trump than any outside group and began its advertising and other efforts earlier than in any other presidential cycle.
And many of its members were visibly elated by Trump's speech Friday.
In remarks before Trump spoke, NRA chief lobbyist Chris Cox recalled the group's endorsement at its convention last year, saying Trump was "the most proudly Second Amendment nominee in American history."
"On Election Day, NRA members and gun owners stormed to the polls in an act of sheer defiance of the elites," Cox said. "And on Inauguration Day, our candidate became our president."
Addressing the group Friday, Trump hailed his first Supreme Court pick, Justice Neil Gorsuch, who was embraced by the NRA, as well as several of his Cabinet selections.
He called Jeff Sessions "a pro-Second Amendment, tough-on-crime attorney general" and touted a decision by his interior secretary, Ryan Zinke, to overturn a federal ban on hunting with lead ammunition in national parks and wildlife refuges.
While making general promises to stand with the NRA moving forward, Trump made no mention of two of the group's leading priorities in Congress.
In the months ahead, the NRA will be looking for Trump to put the weight of his office behind a bill that would make concealed-carry permits valid across state lines. Trump endorsed the concept during the campaign, likening it to the portability of driver's licenses.
Also high on the NRA's agenda is the Hearing Protection Act, which would remove federal registration and identification requirements for those seeking gun silencers. That measure has been touted by the president's son, Donald Trump Jr., an avid hunter, who also attended Friday's conference.
Also left unmentioned Friday was an NRA victory earlier in the Trump administration: His signing of legislation that repealed an Obama-era regulation designed to protect certain mentally ill people from purchasing firearms.
In addition to speaking about gun rights, Trump laced his speech with familiar rhetoric and promises from the campaign trail. He warned of the dangers of "radical Islamic terrorists," called for "putting American first" and pledged to continue a crackdown on illegal immigration.
Trump also played up his promise to build a wall on the U.S. border with Mexico, an initiative dealt a setback in recent budget negotiations over keeping the government open.
"We will build the wall," Trump said. "You need that wall to stop the human trafficking, to stop the drugs, to stop the wrong people."
Trump's speech brought a rebuke from Gabrielle Giffords, a former Democratic congresswoman who survied a 2012 assassination attempt and has become an outspoken gun control advocate.
"We need a president who is serious about finding solutions that will save lives and address the gun violence crisis that's plaguing our nation," she said. "Unfortunately, that's not the president we saw on stage this afternoon in Atlanta."
Trump's appearance Friday at the gun group's massive national convention recalled the triumphant moment a year earlier, when the NRA endorsed him sooner than it had any other candidate in a U.S. presidential election.
He had run on a pro-gun rights agenda, telling the audience at the 2016 NRA convention, held in Louisville, that "crooked Hillary is the most anti-gun, anti-Second Amendment candidate ever to run for office," referencing his Democratic opponent, Hillary Clinton.
This year's convention drew thousands of Trump voters and NRA members from the southern and Midwestern United States. Members of the crowd - almost exclusively white and mostly male - voiced strong support for the president and his agenda, even as they acknowledged some of his efforts remain in limbo.
Gun owners urged the president to push for their agenda with Congress.
"We know that they've got those bigger issues going on right now," said Jon Spears, 37, from Somerset, Ky. "We know that they've got those bigger issues going on right now. We understand that. We're not unreasonable. I just want to hear that they are going to support us down the road."
Like many attendees, Ed Valentine, 67, a resident of the Atlanta suburbs, celebrated the pick of Gorsuch for the Supreme Court. "I hope [he's good]," said Valentine, president of a small environmental engineering firm in the Atlanta suburbs. "You don't know until they get in there."
He also praised Trump's performance in office so far. "Though he could refine his style a little bit!" Valentine said, laughing.
Trump got mostly glowing reviews from conference attendees after his speech.
"I'm hoarse!" said Cathy Boswell of Acworth, Georgia. Her husband, Mike, laughed, saying his hands were sore from clapping.
"He always delivers," Cathy Boswell said. "He doesn't hold anything back, and that's why we love Donald Trump," Mike agreed.
"I thought it was amazing," said Jody Looper, 46, a stay-at-home mom from Mount Juliet, Tennessee. "It's so nice to have a constitutional president again."
A large anti-NRA protest featuring Rep. John Lewis, D-Ga., is scheduled here for Saturday.
But on Friday, dozens of protesters still gathered at nearby Woodruff Park in downtown Atlanta, chanting and holding signs that read "Tiny Bloody Hands." At one point, the group laid down in the grass to represent people killed by gun violence every year, a demonstration they called a "die-in."
Another group gathered outside Atlanta's private Capital City Club, where Trump arrived after his speech to hold a fundraiser for Republican congressional candidate Karen Handel. As Trump's motorcade pulled up, the crowd booed, chanted and beat drums.
Handel finished second in the April 18 special election to Democrat Jon Ossoff; the two will face each other in a runoff on June 20. The race, to replace Republican Tom Price, now Trump's health and human services secretary, is being closely watched nationally as a test of how Trump is affecting down-ballot races.
During his remarks to the NRA, Trump plugged Handel's candidacy, telling convention goers: "She's totally for the NRA, and she's totally for the Second Amendment, so get out and vote."
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)