LOUISVILLE, Ky. (Reuters) - Republican presidential candidate Donald Trump assured gun owners on Friday he would protect their constitutional right to bear arms and eliminate gun-free zones if elected, accusing Democrat Hillary Clinton of wanting to weaken gun rights. Trump, who will almost certainly be the Republican presidential nominee, picked up the endorsement of the National Rifle Association, a politically powerful lobbying group which claims more than 4 million members.  Trump’s remarks at the NRA’s national convention in Louisville, Kentucky, were not a surprise, but they could solidify his status among conservatives who see protecting the U.S. Constitution’s Second Amendment as a top priority.  Trump also planned to meet on Monday with U.S. Senator Bob Corker of Tennessee, a source close to the Trump campaign said. The two are expected to consult on foreign policy. The source said Corker remains on Trump’s list of potential vice presidential running mates. Clinton, who is close to clinching the Democratic Party’s nomination for the Nov. 8 election, has vowed to take on the gun lobby and expand gun control measures to include comprehensive background checks for gun buyers, including at open-air gun shows and online. Trump, who is trying to unite the Republican Party behind him after a brutal primary battle, accused Clinton, a former secretary of state to President Barack Obama, of wanting to end the 2nd Amendment, which says in part that the people’s right to keep and bear arms “shall not be infringed.”  “Hillary Clinton wants to abolish the Second Amendment, not change it; she wants to abolish it,” Trump said. Clinton campaign senior policy adviser Maya Harris said Trump is peddling falsehoods and denounced “Donald Trump’s conspiracy theories.” She said Clinton believes there are “common-sense steps we can take at the federal level to keep guns out of the hands of criminals” while protecting the Second Amendment. Trump told the NRA he would eliminate gun-free zones imposed in some areas, noting that the 2015 shooting deaths of four U.S. Marines at an armed forces recruiting center in Chattanooga, Tennessee, took place in a gun-free zone. “The Second Amendment is on the ballot in November,” he said. “The only way to save our Second Amendment is to vote for a person you know: Donald Trump.” The NRA’s convention took place on the same day that a man brandished a gun at a checkpoint near the White House in Washington and was shot and wounded by a law enforcement officer. The New York billionaire’s NRA speech was another step in his drive to make more conservatives comfortable with his candidacy. Earlier this week, he released a list of 11 potential Supreme Court nominees who are conservative jurists, a step well-received on the right. Many conservatives, who had backed other Republican candidates in the 2016 race, worry that Trump is a closet liberal on many issues. But Chris Cox, executive director of the NRA’s Institute for Legislative Action, said it was time for them to get over their qualms about the 69-year-old candidate. “If your preferred candidate is out of the race, it’s time to get over it,” Cox told the NRA audience. “Are there valid arguments in favor of some over others? Sure. Will any of it matter if Hillary wins in November? Not one bit.” In another step toward trying to unify the party, Cox has invited members of Congress to a “small roundtable discussion” with one of Trump’s sons, Donald Trump Jr., on Wednesday at the Capitol Hill Club near the U.S. Capitol, a copy of the invitation said.  