In her strongest comments yet on the issue, Hillary Clinton tore into rival Bernie Sanders’ record on gun control Friday evening in an exclusive interview with MSNBC’s Chris Matthews. “When it really mattered, Sen. Sanders voted with the gun lobby, and I voted against the gun lobby,” Clinton told Matthews, referring to Sanders’ vote for a bill to grant immunity to gun makers from lawsuits when their products are used in crimes. Calling the immunity law the National Rifle Association’s “most important priority in 20 years,” Clinton said Sanders had shown no interest in reversing course. “I’ve raised this issue before, standing next to Sen. Sanders,” Clinton continued, referring to the Democratic debates. “He’s refused to give a straight answer. He could, today, introduce legislation to repeal the immunity that was given to gun makers and sellers. I hope he will join me and the president in supporting real change. And that’s what I’m looking for.” Clinton and Sanders have been trading barbs on guns this week as the White House makes a major push around executive actions President Obama is taking to increase gun safety regulations. “So this is a significant difference, and it’s important that, you know, maybe it’s time for Sen. Sanders to stand up and say I got this one wrong. But he hasn’t,” Clinton said in the interview. “He’s defended his vote time and again. He said he would consider changes to the law, but, you know, that was three months ago and there’s been no [motion] to introduce anything in the Congress or to stand with, you know, those Democrats who want to repeal this, you know, really irresponsible blanket immunity that was voted in for the gun makers and sellers.” On Friday, Clinton’s campaign said that Sanders was out of step with the White House and suggested that Obama would not campaign for the Vermont senator if he won the Democratic primary. They made the accusation based on a New York Times op-ed Obama published warning that he would not support any candidate for president of either party who did not align with him on guns, including repealing the immunity law. The White House seemed to side with Clinton Friday, saying it was news that Sanders would consider reversing course on the immunity law. The Sanders campaign did not immediately respond to MSNBC’s request for comment. Gun control has been a major issue in the Democratic primary for months, as Clinton has used it as a way to outflank Sanders on his left. But she’s stepped up her attacks as the White House has invested in the issue. But Clinton’s criticism of Sanders’ record went beyond the immunity law. “I think Sen. Sanders has been wrong on gun safety and that he’s wrong on the fact that this is the leading cause of death for young people in our country, particularly young African-American men,” Clinton told Matthews. “So it represents a very clear choice in a Democratic primary.” And there was more. “Sen. Sanders voted five times against The Brady Bill, five times. And it has been the principal instrument for us keeping more than 2 million guns out of the hands of fugitives, felons, stalkers, the people who should not have them in the first place,” she said. “He voted against closing loopholes,” she continued, accusing Sanders of voting for the so-called Charleston loophole. And she said he voted to allow guns on Amtrak trains as well. She said this was “a pattern” with Sanders in opposing gun control, “and it’s a pattern that I have been calling out.” Sanders has defended his record on guns by noting that Vermont is a rural state with almost no control He has said he could have a moderating impact on the gun debate bridging urban and rural America.