Factual errors: When Curly Bill Brocius is shot by Wyatt Earp, only a tiny entrance wound is shown in his forehead as he falls over, even though Earp fired a shotgun. A shotgun blast would have blown Brocius's head apart.
Factual errors: In fact, when ambushed, Virgil Earp was shot in his left elbow, but in the movie he has immobilized his right arm.
Factual errors: In the O.K. Corral duel time, the county sheriff was John Behan, not Jimmy Bryan according to the movie.
Revealing mistakes: When Virgil Earp is ambushed while doing his rounds he is shot by Frank Stilwell using a double barrel shotgun. In spite of the distance between him and Stillwell in the Barber Shop (the width of a street) there are no pellet strikes in the building he is standing in front of.