Sen. Dianne Feinstein (D-Calif.) chided her colleagues for shooting down gun control amendments before her assault weapons ban renewal met the same fate.

It failed 40-60, with both red-state and blue-state Democrats voting against the ban.

Feinstein expressed “substantial dismay at the lack of courage in this house” at the day’s votes, which included the 54-46 failure of the Manchin-Toomey amendment on background checks.

“We have had enough of the development of highly militarized weapons,” she said. “Everything needs 60 votes today — this is supposed to be a majority body.”

Ironically, Senate Majority Leader Harry Reid (D-Nev.) likely didn’t seek a unanimous consent agreement for a simple majority because he feared gun-rights amendments would get attached to his bill. Reid also angered Feinstein by not rolling her assault weapons bill into his gun-control package.

More Democrats have come to the gun-rights side throughout the afternoon’s votes than Republicans siding with gun control measures.

However, Feinstein’s amendment still would have fallen far short of the simple majority threshold.

“I know how this is going to end and the despair and dismay of those families… I am really chagrined and concerned,” Feinstein continued. “…Show some guts!”

Sen. Chuck Grassley (R-Iowa), though, rose to defend Second Amendment rights in an equally impassioned tone, slamming Feinstein’s amendment as the “largest ban of guns in the history of our republic.”

“It did not stop Columbine; it would not stop Newtown,” Grassley said. “Criminals who steal such guns would not care if they were banned.”

As the ranking member on the Judiciary Committee, Grassley had asked for analysis of the constitutional ramifications of the assault weapons ban from the Justice Department but did not receive a response.

Based on Supreme Court precedent, he said, “they cannot be banned.”

Grassely warned “this is a slippery slope” of yielding more and more constitutional rights.

Sen. Mark Udall (D-Colo.) was among the “no” votes. “In carefully studying the language of this specific assault weapons ban, it became clear that it went too far because it also would have banned certain hunting rifles and even some shotguns,” he said. “And there was no opportunity to amend this legislation to make it work for Colorado sportsmen.”

UPDATE: An amendment by Sen. Richard Blumenthal (D-Conn.) to limit ammunition magazines to ten rounds has failed 46-54.

UPDATE: Feinstein after her 20-point defeat: “I’m disappointed by today’s vote, but I always knew this was an uphill battle. I believe the American people are far ahead of their elected officials on this issue, and I will continue to fight for a renewed ban on assault weapons,” she said.

“The very fact that we’re debating gun violence on the Senate floor is a step in the right direction, and I hope my colleagues vote their conscience and approve the underlying bill. But I’m certain that in the coming months and years, we will be forced to confront other incidents like Newtown, where innocents are murdered with one of these weapons of war.”