The senator said efforts to expand background checks to firearms purchasers at gun shows and over the Internet weren't over though the legislation he drafted with Republican Patrick Toomey of Pennsylvania failed to receive the 60 votes needed to advance in the Senate.
Manchin, who called the bill "something that makes so much sense and it's common sense," said he was trying to pick up support from some senators who had voted no.
"As a law-abiding gun owner, I'm not going to sell my gun to a stranger, not going to sell to someone who's mentally deranged, or to a family member who basically is not responsible," Manchin said. "I'm at 50-50 to where I think we can pick up five more members."
Manchin, who sits on the Senate Armed Services Committee, cautioned about U.S. involvement in Syria, where the United Nations estimates at least 80,000 have died since a rebel uprising against President Bashar al-Assad began in 2011. After the U.S. ousted Saddam Hussein in Iraq, Iran gained in influence and democracy didn't take hold, Manchin said.
"We've proven that, if you remove one, there's something as bad, if not worse," Manchin said. "What's Syria's neighbors' feeling about this? That's their neighborhood."
Manchin said the Democrats "have a shot" at keeping the West Virginia Senate seat being vacated by retiring Jay Rockefeller, though it "will be a challenge."
He predicted the party will find a "very viable" candidate to oppose Republican Rep. Shelley Moore Capito, considered the front-runner for the Senate seat.
"It will be a challenge to hold that seat," he said. "I understand that. Our state demographics have changed."
Other Top HeadlinesSkaff announces plans to run for Senate seat