"The Second Amendment is on the ballot in November," Trump said. Screenshot/NRA Donald Trump is trying out a new nickname for Hillary Clinton: "Heartless Hillary."

Trump was speaking at the National Rifle Association on Friday, and he attacked Clinton on the issue of guns. The NRA endorsed Trump for president.

In a speech following the endorsement, Trump attacked Clinton on her policies, claiming she would "abolish the Second Amendment" and disarm people who want to defend themselves against criminals.

"Hillary wants to disarm vulnerable Americans in high-crime neighborhoods," Trump said.

"Whether it's a young single mom in Florida or a grandmother in Ohio, Hillary wants them to be defenseless. Wants to take away any chance they have of survival," he said.

Trump said there is "tremendous crime of all kinds" in America.

People "need to be protected," he said. "And you know the only way they're going to be able to protect themselves. And if you take that gun away from them, it's going to be a very unfair situation. And that's why we're going to call her 'Heartless Hillary.'"

Trump did admit, however, that "somehow" he still likes "Crooked Hillary" — his usual name for his Democratic rival — better than the new nickname.

Clinton and Trump, most likely headed for a general-election matchup in November, appear set to clash on guns. Clinton has made the issue a signature one during her primary campaign against Sen. Bernie Sanders, as it has been a rare point where their views diverge.

Last week, in preparing for the likely battle ahead, her account tweeted that Trump would force schools to allow guns in classrooms.

Throughout his Friday speech, Trump sought to portray the general election as a choice between upholding the Second Amendment and stripping citizens of their constitutional rights.

"The Second Amendment is on the ballot in November," Trump said.