A travesty of a film, and one in which the usually competent Philip Carey and Joseph Cotton disappoint, though at least the latter can have claimed he was playing an often-drunken Major Reno. Darren McGavin stomps and jerks around as "Captain Bill Benton", so-called presumably because there is little relation with the real-life Captain Benteen. "Benton" is hazed by Reno, is keen on his daughter, strikes Custer, is captured/rescued by the Indians on his way to court-martial, is rescued again (this time by the cavalry), rides to warn Custer of the Indians' strength and is reinstated to lead his men at the fateful battle.
Individuals change their characters as the film progresses: Custer switches from idealism and anger at governmental corruption to political ambition; Reno evolves from drunk to semi-hero, in between resenting command of the 7th being offered to Benton (both then becoming self-deprecatory about their ability to lead); and the scout Dakota suddenly switches from hating and killing Indians to saving them (and when he deserts he is shot making a mad dash from the cavalry bivouac rather than slip away when scouting ahead of the column). Some of the minor actors appear to be waiting for cues or direction, and riders shot off their horses fall to the ground as safely as possible. Often the dialogue is artificial: "I shall see you trouble my existence no longer," rasps Custer to Reno at one point.
The film starts and finishes with the sort of completely unrealistic military court hearing that mars several Westerns; in this case the evidence comes entirely from Benton, with no other witnesses being called.
The Battle of the Little Big Horn isn't too bad but apparently the footage was borrowed from "Sitting Bull" made ten years earlier. Certainly when the main characters are on screen they appear to be accompanied by only a handful of men.
By 1965 Hollywood should have been able to do better than this.