Circa 1990s. It takes place in the future but a time machine is involved. A big-game hunter takes people on hunting expeditions to pre-historic times to hunt dinosaurs. The only catch is the hunters are only allowed to kill the dinosaur at the precise time that it actually dies. If it is killed before it died in the past, then they are changing the past which could have drastic results in the future. One hunter panics and kills a dinosaur less than a minute before it was scheduled to die. hen the hunters return to the future they find out that it has been changed-it changes to something like a Big Brother government.

It may have actually been from a tv show and not a movie.