West Virginia Democratic Sen. Joe Manchin III, who has had the support of the National Rifle Association, joined the call for a conversation about new gun control measures Monday in the aftermath of the Dec. 14 mass shooting at a Connecticut elementary school.

Manchin expressed an openness to new regulations, including the possibility that he would support reviving a ban on assault weapons and restrictions on high-capacity clips being championed by Sen. Dianne Feinstein, D-Calif., and others.

“I think when you look at it, if Dianne’s saying that basically assault weapons … I don’t know anyone in the sporting or hunting arena that goes out with an assault rifle. I don’t know anyone that needs 30 rounds in a clip to go hunting,” Manchin said Monday on MSNBC.

“I think opening up and seeing the massacre of so many innocent children, it’s changed,” Manchin told MSNBC’s “Morning Joe.” “It’s changed America. We’ve never seen this happen.”

Manchin famously used a rifle to shoot a copy of the president’s cap-and-trade bill in one of his campaign television commercials. He’s an avid sportsman — and represents exactly the kind of Democrat that gun control advocates need to win over to have a prayer of passing any legislation through Congress.

Feinstein announced Sunday that she would reintroduce an assault weapons ban bill on the first day of the new Congress in January.

Manchin and Feinstein come from very different states and very different backgrounds. Feinstein first became mayor of San Francisco following the 1978 murders of Mayor George Moscone and supervisor Harvey Milk, when Feinstein served as president of the board of supervisors. She has long advocated for more stringent gun control.

Manchin, by contrast, has an “A” rating from the NRA. The group’s political arm endorsed Manchin’s candidacy both times he ran for Senate in 2010 and 2012.

“Voters in West Virginia can trust that Joe Manchin will respect their right to self-defense and will honor their rich hunting heritage,” Chris W. Cox, the NRA’s top lobbyist, said in a statement endorsing Manchin.

But Monday on MSNBC Manchin called for the NRA to join the conversation about guns, mental health and other issues following the mass murder of 26 teachers and students at Sandy Hook Elementary School in Newtown, Conn.

“I want to call all our friends at NRA and sit down, and bring them into it,” Manchin said. “They have to be at the table. We all have to.”

Manchin also expressed support for a suggestion made Sunday by Sen. Joseph I. Lieberman, I-Conn., to establish a federal commission on violence.