2020 contender Pete Buttigieg told CNN on Sunday that Beto O'Rourke's remark of "Hell yes, we're going to take your AR-15" plays into the hands of Republicans on gun control.O'Rourke's Twitter response: "Leaving millions of weapons of war on the streets because Trump and McConnell are 'at least pretending to be open to reforms'? That calculation and fear is what got us here in the first place. Let’s have the courage to say what we believe and fight for it."CNN'S JAKE TAPPER: 2020 candidate Beto O'Rourke raised some eyebrows by saying, 'Hell yes, we're going to take your AR-15, your AK-47,' at the debate. Democratic Sen. Chris Coons of Delaware who has endorsed Biden, he has responded by saying this: 'That clip will be played for years at second amendment rallies for organizations who try to scare people by saying Democrats are coming for your guns.' Do you agree? Did Beto O'Rourke say something that's playing into the hands of Republicans?BUTTIGIEG: Yes. Look, right now, we have an amazing moment on our hands. We have agreement among the American people for not just universal background checks, we have a majority in favor of red flag laws, high-capacity magazines, banning the new sale of assault weapons. This is a golden moment to finally do something, because we've been arguing about this for as long as I've been alive. When even this president and even Mitch McConnell are at least pretending to be open to reforms, we know that we have a moment on our hands. Let's make the most of it and get these things done.Why it matters: The candidates' clash represents a growing rift within the Democratic party between moderates and progressives, who are increasingly finding themselves misaligned on issues including health care, immigration and approaches to legislating.What they're saying: On NBC's "Meet the Press" on Sunday, O'Rourke also said he refuses to acknowledge the "politics or the polling" on AR-15s, stating Democratic backlash "just shows you how screwed up the priorities in Washington, D.C., are."Go deeper: Democrats' watershed moment on guns