Though her ban on certain styles of rifles lapsed a decade ago, Sen. Dianne Feinstein (D., Calif.) continues to push for its reinstatement and tout its effectiveness.

A new fact-check from Pro Publica found Feinstein's Clinton-era assault weapons ban had no noticeable effect on crime.

In the ten years since the federal assault weapons ban expired, Sen. Dianne Feinstein has kept trying to renew the law, which she authored. In a press release this month honoring the 20th anniversary of the ban, she wrote, "The evidence is clear: The ban worked." But gun violence experts say the exact opposite. "There is no compelling evidence that it saved lives," Duke University public policy experts Philip Cook and Kristin Goss wrote in their book The Gun Debate: What Everyone Needs to Know.

The Democrat senator relies on a 1997 study to declare her gun ban a success–but that study's findings have been discredited by more recent studies.

A definitive study of the 1994 law–which prohibited the manufacture and sale of semiautomatic guns with "military-style features" such pistol grips or bayonet mounts as well as magazines holding more than ten rounds of ammunition–found no evidence that it had reduced overall gun crime or made shootings less lethal. "We cannot clearly credit the ban with any of the nation's recent drop in gun violence," the Department of Justice-funded study concluded in 2004. "Should it be renewed, the ban's effects on gun violence are likely to be small at best and perhaps too small for reliable measurement."

One of the authors of the study Feinstein cited even said the results were only preliminary and have since been superseded by more recent research.

But one of the authors of that study, Dr. Christopher Koper, a criminologist from George Mason University, told ProPublica that number was just a "tentative conclusion." Koper was also the principal investigator on the 2004 study that, as he put it, "kind of overruled, based on new evidence, what the preliminary report had been in 1997."

Feinstein contested criticism of the study and says its findings are still valid. However, Koper has completely shifted his view.

"The weight of evidence that was gathered and analyzed across the two reports suggested that initial drop in the gun murder rate must have been due to other factors besides the assault weapons ban," Koper said.

Gun rights activists have long considered the gun ban ineffective and say Feinstein misleads Americans about its results as well as her intentions.