Vin Diesel's Riddick is headed for a No. 1 finish at the domestic box office, although it may not cross $20 million in its debut. The threequel topped the Friday box office with $7.3 million, putting it on course for an $18 million to $19 million weekend. Prerelease tracking had suggested the Universal release would open north of $20 million, although Universal was more conservative in its estimate. Read more http://www.hollywoodreporter.com/news/box-office-riddick-no-1-623644 [video=youtube;tDxDEjDMreA]http://www.youtube.com/watch?v=tDxDEjDMreA[/video]