The romantic comedy "40 Days and 40 Nights," starring Josh Hartnett and Shannyn Sossamon, opened in second place with $12.5 million, which a studio spokesman said was on target.
Hartnett plays a jilted lover who gives up sex for the titular period in order to get over his ex-girlfriend.
Last weekend's No. 1 movie, the vampire tale "Queen of the Damned," suffered the curse of many horror flicks and tumbled to sixth place with $5.8 million. Fright films often debut strongly as hardcore horror fans turn out in big numbers, then plummet the next weekend.
Receipts for "Queen of the Damned," featuring the late pop singer Aaliyah as an ancient vampire, dropped 61 percent from the movie's opening weekend. In contrast, Denzel Washington's "John Q" grossed $8.4 million in its third weekend and Kevin Costner's "Dragonfly" took in $6.8 million in its second, both down just 33 percent.
"It's not too abnormal to see big drop-offs on a horror movie," said Dan Fellman, head of distribution for Warner Bros., which released "Queen of the Damned."
"We Were Soldiers" is the latest in a parade of war movies that went into production well before Sept. 11, but are riding a wave of patriotism since the terrorist attacks. It's a rare Vietnam movie that presents U.S. soldiers in a good light as honorable comrades in arms.
"I think certainly the Sept. 11 incident puts people more in the mood for wanting to cheer for the American soldiers," said Wayne Lewellen, head of distribution for Paramount, which released "We Were Soldiers."
About 75 percent of the audience for "We Were Soldiers" was older than 25. War films usually draw a heavily male audience, but women made up a strong 44 percent share of the crowds.
"I think Mel Gibson may have had something to do with that," Lewellen said.
Gibson stars as Lt. Col. Hal Moore, who led about 400 outnumbered American troops in the first major battle against the North Vietnamese in 1965.
Unlike such aging actors as Costner and Arnold Schwarzenegger, whose recent films have posted lackluster returns, "Mel Gibson is an absolute rock solid star. He just continues to roll along," said Paul Dergarabedian, president of Exhibitor Relations, which tracks the box office. "He keeps enthralling audiences with virtually everything he does."
"40 Days and 40 Nights" benefited from a market fairly empty on light romances for the date crowd. Hartnett stars as a man tempted by a new woman in his life after he vows to give up sex for Lent.
The audience for "40 Days and 40 Nights" was about 60 percent women and was heavy on movie-goers between 17 and 25, said David Kaminow, senior vice president of marketing for Miramax, which released the movie.
"We saw this as a good weekend for romantic comedy," Kaminow said. "We knew the Mel Gibson movie would probably skew a little older and saw an opportunity for the next couple of weekends for a movie that appeals to more of a female audience."
Leading Academy Award nominee "The Lord of the Rings: The Fellowship of the Ring" (AOL's New Line) returned to the top 10 after a two-week absence, jumping two spots to the final rung with $3.1 million. After 11 weekends, the adventure fantasy has grossed $287.4 million. Its 10 percent fall was the slightest in the top 10. The film has 13 Oscar nominations.
Estimated ticket sales for Friday through Sunday at North American theaters, according to Exhibitor Relations Co. Inc.
"We Were Soldiers," $20.2 million.
2. "40 Days and 40 Nights," $12.5 million.
3. "John Q," $8.4 million.
4. "Dragonfly," $6.8 million.
5. "Return to Never Land," $6.5 million.
6. "Queen of the Damned," $5.8 million.
7. "Big Fat Liar," $4.8 million.
8. "A Beautiful Mind," $4.4 million.
9. "Crossroads," $4 million.
10. "The Lord of the Rings: The Fellowship of the Ring," $3.1 million.