Factual error: The film is set during the late 1880's in India. The rifles/bayonets carried by all the British soldiers and Thuggee Indians are American 1890's Krag-Jorgensen rifles. Presumably done for ease of supplying American ammunition compared to British .303 ammunition.
Gunga Din (1939)
1 factual error - chronological order
Directed by: George Stevens
Starring: Cary Grant, Joan Fontaine, Sam Jaffe, Victor McLaglen, Douglas Fairbanks Jr.
Continuity mistake: When the curtain gets stuck to Ballantine's pants, at first it's stuck on his side, then in the next shot it's stuck in the middle of his back.
Sgt. Archibald Cutter: Now you're all under arrest. Her Majesty's very touchy about having her subjects strangled.