Continuity mistake: When Francis Fryer throws the cowboy he loses the scarf in his hand but when the camera angle changes he has it again.
Visible crew/equipment: When Calamity and Katie are driving back on the stage they are attacked by Indians before they arrive in town. Calamity starts shooting at them from behind the large suitcase with Adellaid Adams wrote on it. Initially there is no mark on the suitcase but halfway through the scene a black mark appears below the D of Adellaid and if you look very closely you can see the piece of string along which the arrow is shot.
Continuity mistake: In the scene after the dance, when Calamity and Wild Bill Hickok return to her place, she is wearing a fancy, floor-length off-the-shoulder dress - no straps. Calamity asks Bill to turn around so she can change. After Bill turns, the cut back to Calamity reveals her wearing an undergarment with wide straps over the shoulders and a pair of bloomers. No way that garment could have been under that dress.