Watch Sanders and Clinton Go Head-to-Head on Gun Control

Martin O'Malley also jumped in the fray, citing Clinton's "Annie Oakley" moment of opposing federal gun regulations

The Democratic presidential candidates tackled the issue of gun control at Saturday's CBS News debate.

At the CBS News Democratic debate Saturday, the candidates waded into the issue of gun control — one of the few policy areas in which Bernie Sanders is generally considered to the right of Hillary Clinton.

Asked about the difference between her and Sanders' stance on guns, Clinton said, "I know Sen. Sanders had a different vote than I did when it came to giving immunity to gun makers and sellers." She called his vote a "terrible mistake" that "gave the gun lobby even more power to intimidate legislators not just in Washington, but across the country."

She went on to note that since the last Democratic debate, in October, "nearly 3,000 people have been killed by guns; 21 mass shootings, including one last weekend in Des Moines, where three were murdered.; 200 children have been killed. This is an emergency."

"There are a lot of things we have to do in our country — reigning in Wall Street is certainly one of them, I agree with that," Clinton said, in a nod to Sanders, "but we also have to go after the gun lobby."

Debate moderator John Dickerson had a rejoinder for Clinton: "You say that Sen. Sanders took a vote on immunity that you don't like. So if he can be tattooed by a single vote, and that ruins all future opinions by him on this issue, why then isn't he right when he says your wrong vote on Iraq tattoos you forever in your judgement?"

"I said I made a mistake on Iraq," Clinton said.

In response, Sanders said he'd like to "do more than reverse the immunity.... I have voted time and again for the background check, and I want to see it improved and expanded. I want to see us do away with the gun show loophole."

"I don't know that there's any disagreement here," he said.

Martin O'Malley also jumped into the fray, hitting back at Clinton by saying she's been "on three sides" of this issue, citing Clinton's shift on gun control: "When you ran in 2000, you said that we needed federal robust regulations. Then, in 2008, you were portraying yourself as Annie Oakley and saying that we don't need those regulations on the federal level. And now you're coming back around here."

"There's a big difference in leading by polls, and leading by principle," he said.