Democratic presidential front-runner Hillary Clinton called on rival Bernie Sanders (Vt.) to commit to repealing a gun manufacturer liability law for which he voted in 2005, doubling down on her efforts in recent days to cast her vote against the law as a significant difference between the two candidates.

The law shields gun manufacturers from certain lawsuits, including for negligence and certain types of claims relating to the gun's design. The law does not guarantee blanket immunity, but it does provide a unique legal shield that most manufacturers of consumer goods do not have.

Sanders told supporters during a rally in Iowa on Saturday that he would change the law to allow gun manufacturers acting "irresponsibly" to be held accountable. But Clinton continued pressing the issue, accusing Sanders on Sunday of not committing to repealing the law.

"I think he has been consistently refusing to say that he would vote to repeal this absolute immunity from any kind of responsibility or liability," Clinton said on CBS's "Face the Nation."

Sanders "often says, well, look, I'm from Vermont and it's different. It's not like being in New York City," Clinton said. "Well, in fact, the other senator from Vermont, Senator [Patrick] Leahy, voted with President Obama and myself. So I think that the excuses and efforts by Senator Sanders to avoid responsibility for this vote, which the NRA [National Rifle Association] hailed as the most important in 20 years, points up a clear difference."

Asked about his vote on ABC's "This Week" on Sunday, Sanders said it was "a complicated piece of legislation. There were aspects of it that were absolutely right. There were aspects of it that were wrong." He added that he will vote to revise the law.

"Look, I've cast over 10,000 votes in my life, and many pieces of legislation are complicated. They have good stuff in it. They have bad stuff in it," Sanders said. "I am absolutely willing to take another look at that legislation and get rid of the onerous provisions. When gun manufacturers, for example, are selling guns into an area and know that those guns are getting into the hands of criminals, absolutely, those gun manufacturers should be held accountable."

Sanders said owners of gun shops who act legally should not be held liable for the actions of someone who "goes nuts or something, and he kills somebody."

"On the other hand, if you have a manufacturer that is sending guns into an area and really knows that those guns are not being used by the people or bought by the people in that area but are being sold to criminals, should we hold that manufacturer liable? Absolutely," Sanders said.