NRA Executive Vice President Wayne LaPierre's attendance at the hearing once again put him at odds with Sen. Dianne Feinstein (D-Calif.), a senior member of the Judiciary Committee who is leading the push for a new assault-weapons ban. The two have sparred before at congressional hearings and on national television over gun-control efforts.

Feinstein did not question LaPierre when it was her turn to address witnesses, but did acknowledge their long history: "It’s good to see you again," she said to LaPierre. "We tangled — what was it? — 18 years ago. You look pretty good."

Feinstein told reporters Tuesday that she didn't "want to get into a back and forth" with LaPierre, adding that, "He wants one thing, I want an entirely different thing. He's there for gun people, to allow them to have these guns regardless. They have fought virtually every kind of regulation. The time has come to change course, and the time has come to see what makes people safe."