Two of the nation’s largest gun control advocacy groups have endorsed Joe Biden, the latest sign that Bernie Sanders’ spotty record on guns may be weighing him down in the presidential primary.

Everytown for Gun Safety and Brady announced they are backing the former vice president.

Everytown for Gun Safety Action Fund plans to spend $60 million on electoral activities this cycle, some of which will go toward trying to elect Biden. An Everytown spokesman said the group typically airs advertisements and engages in grassroots organizing for the candidates it endorses, though it’s unclear when the group will begin to spend on Biden’s behalf. The group, which was co-founded by billionaire former New York Mayor Mike Bloomberg, also boasts 6 million supporters and more than 375,000 grassroots donors, numbers that could help boost attention and support for Biden’s presidential bid nationwide.

Brady, another leading gun violence prevention group, endorsed Biden on Sunday. The group said in a statement that as a senator, Biden worked with Jim and Sarah Brady to pass the landmark Brady Bill, which established mandatory background checks for gun sales. Biden also championed a 1994 federal assault weapons ban.

“Joe Biden has worked with the gun violence prevention movement, with survivors and with lawmakers his entire career,” Brady President Kris Brown said. ”We know him, and he knows us. We know he will work to deliver this change.”

Biden said he was honored to receive the endorsements and lamented that the high rate of gun violence in the U.S. has become “normal” for most Americans. For those who are connected to gun violence, “normal is a living nightmare,” Biden said.

In an interview with The Associated Press, John Feinblatt, head of Everytown for Gun Safety, said the group chose Biden because working for gun control is “his past, it’s his present, it’s his future.” Asked if Sanders’ record on gun control factored into the group’s decision, Feinblatt said that the group looks at a candidate’s “total record.”

“You can’t confine yourself to just what somebody says they’ll do in the future. You have to look at what they’ve done in the past,” he said. “Unquestionably, Joe is a person who’s dedicated much of his life to the issue of gun safety.”

Feinblatt cited Biden’s support for the 1993 Brady Bill, which established background checks and a waiting period to buy most firearms, as well as Biden’s opposition to measures that would shield gun manufacturers from lawsuits over misuse of their guns. He also pointed to Biden’s work on the Violence Against Women Act, which included some gun control provisions.

During his tenure in the House and the Senate, Sanders opposed the Brady Bill and supported bills that would give gun manufacturers immunity from lawsuits. His position on gun control issues has shifted, and he now has a D-minus rating from the National Rifle Association.

But Sanders’ past votes have been frequent fodder for attacks from his opponents, dating back to his 2016 Democratic primary fight with Hillary Clinton. Most recently, Sanders came under attack during the South Carolina debate two weeks ago from multiple opponents for his record on guns, with Biden charging, as he stood next to the Vermont senator, that “my friend on my right and others have given gun manufacturers absolute immunity.”

Biden also has run ads highlighting his work on gun control measures. “I’ve taken on the NRA and defeated them twice,” he said. “And I believe we need a candidate for president who will fight alongside these leaders, not the NRA or gun manufacturers.”

Everytown for Gun Safety is largely financed by Bloomberg, a former 2020 presidential candidate who dropped out of the race and endorsed Biden last week.