The National Rifle Association endorsed Donald Trump on Friday, just before the apparent Republican nominee addressed its annual conference in Louisville, Ky.

"To get the endorsement, believe me, is a fantastic honor," Trump said, adding that he and his sons are members of the NRA. "They're much better shooters than I am," he said.

"They have so many rifles and so many guns, I tell you, sometimes even I get a little concerned," Trump said.

Saying the Second Amendment is "under attack" and "on the ballot in November," Trump laid out his case as the best candidate for protecting gun rights and he hit at Hillary Clinton's stance on guns. He also called her "unqualified to serve as president of the United States." (Trump was invoking Bernie Sanders, who questioned Clinton's qualifications at a debate.)

"The only way to save our Second Amendment is to vote for someone you know named Donald Trump," he said. "I will never let you down."

Trump also called for gun-free zones, which he also called for in a tweet last summer. "We're getting rid of them," he said. He spoke about the 2015 shooting in Chattanooga, Tenn., that killed five people and occurred in a gun-free zone on a military installation.

However, several Trump properties, including Mar-a-Lago and Trump International Hotel in Chicago, tell NPR that guns are not allowed on the premises.

Clinton and Trump, now likely opponents in the general election, are sure to increasingly clash on the issue. Clinton favors stricter background checks and holding dealers and manufacturers liable for crimes committed with their weapons.

"Hillary Clinton wants to abolish the Second Amendment ... we're going to preserve it, we're going to cherish it, we're going to protect it," Trump said. "Crooked Hillary Clinton is the most anti-gun, anti-Second Amendment candidate ever to run for office." Trump also called Clinton a "heartless hypocrite" for wanting to "take away guns," while having bodyguards for protection.

Trump, meanwhile, said he would "guarantee that law-abiding Americans have the right to self-defense, 100 percent."

"Without defense, we don't have a country," he said, adding that he feels it is more important than economic issues.

This campaign, Trump has previously vowed to "totally protect" the Second Amendment, and has said more gun ownership would help prevent mass shootings. He echoed that theory in his remarks Friday while talking about recent shootings in Paris and San Bernardino, Calif. "If we had guns on the other side, it wouldn't have been that way," he said. "I would have — boom," he continued, making a gun gesture.

Trump's current stance on guns is a shift from the candidate's earlier statements on the issue.

In 2000, he supported a ban on assault weapons and longer waiting periods, as he wrote in his book The America We Deserve (h/t NPR's Sarah McCammon):

"I generally oppose gun control, but I support the ban on assault weapons and I support a slightly longer waiting period to purchase a gun. With today's Internet technology we should be able to tell within 72-hours if a potential gun owner has a record."Copyright 2016 NPR. To see more, visit