The Vermont senator and his Democratic liberal base are simpatico on nearly every policy area -- but gun control has long been an exception. Hailing from a rural state with few gun restrictions, Sanders has sought a middle ground.
It's an issue all but certain to come up Tuesday night in Las Vegas, when the Democratic presidential field meets for its first debate following three recent campus shootings.
In an interview with NBC's Chuck Todd set to air Sunday on "Meet the Press," Sanders said that in Washington, lawmakers "keep shouting at each other, which is what's been going on here for 20 years" and it "ain't going nowhere."
He said he sees an opening to advance "common sense gun reform" as well as "a revolution in mental health."
"When the vast majority of the American people say it's pretty crazy that guns are falling into the hands of people who are either criminals or mentally ill and they're shooting up kids -- yeah, I think we can build on that," he said.
Sanders' record on gun control has angered both anti-gun groups and the National Rifle Association.
He has supported universal background checks for gun buyers, a ban on assault weapons and the closure of the so-called gun show loophole that allows sales to take place without background checks.
But he has also voted to allow guns in national parks and on Amtrak trains, opposed a five-day waiting period for gun purchases and backed for a 2005 measure that shielded gun manufacturers from liability in lawsuits over shootings.
Sanders was pressed Sunday on that 2005 vote -- one that's drawn new criticism from liberal groups during his presidential bid. He said he's open to "another look" at the issue.
"That was a complicated vote and I'm willing to see changes in that provision," Sanders said. "Here's the reason I voted the way I voted: If you are a gun shop owner in Vermont and you sell somebody a gun and that person flips out and then kills somebody, I don't think it's really fair to hold that person responsible, the gun shop owner.
"On the other hand, where there is a problem is there is evidence that manufacturers, gun manufacturers, do know that they're selling a whole lot of guns in an area that really should not be buying that many guns. That many of those guns are going to other areas, probably for criminal purposes. So can we take another look at that liability issue? Yes."
The vote to protect gun manufacturers from lawsuits could hurt Sanders the most. In the past he has voted to make it easier to sue airlines for crashes over water, machine tool makers for injuries that happen after 18 years of use, restaurants over mislabeled food that contributed to weight gain and more.
It's not clear how many of Sanders' supporters would be turned off by his gun votes. Russell Mendell, a 30-year-old Democratic voter in Boulder, Colorado, said he won't hold those votes against him.
"I think you can go back on any candidate who has been around for 30 years and find some issues that you don't agree on," he said. "I agree with Bernie Sanders on about 95 to 96 percent of things. I am not going to agree with any candidate all the time."
Sanders also talked guns at a rally in front of 13,000 people Friday night in Tucson, Arizona.
"It goes without saying that our condolences go to the families of those who were killed and our hearts and prayers go out for a full recovery for those who were wounded," Sanders said after mentioning shootings at Texas Southern University and Northern Arizona University. "But we also know that we are tired of condolences and we are tired of just prayers."
Sanders argued that while the issue of gun control is "not going to be solved easily," that "does not mean we do not address it and do the best we can."
"Yes there are disagreement on how we go forward in terms of gun safety," Sanders said. "But I think the vast majority of the American people want us to move forward in sensible ways which keep guns out of the hands of people who should not have them."