Other mistake: Bandoleer rounds don't fit any weapon in the show. When Pierce tries the Gatling gun, there is no magazine in it.
Other mistake: When Lomax enters the War Wagon after it has overturned, the safe door is already partially opened.
The War Wagon (1967)
2 other mistakes - chronological order
Directed by: Burt Kennedy
Starring: John Wayne, Kirk Douglas, Howard Keel, Robert Walker Jr.
Genres: Western
Continuity mistake: While every other actor in this movie wears the same costume day and night, day after day, John Wayne's costume changes regularly, even between shots. For all daytime scenes, he wears an orange long-sleeved shirt with a contrasting blue neck-kerchief; in some night-time scenes, he wears a blue long-sleeved shirt with a contrasting yellow neck-kerchief; and sometimes his daytime neck-kerchief changes from blue to yellow in a matter of seconds, between shots.
Frank Pierce: Get fresh horses - I want you in Rondado before sun-up. Find Lomax. I want him to kill Taw Jackson. I'll pay him anything he wants.
Hammond: You'd pay him anything, sir?
Frank Pierce: I'll go for ten thousand.
Hammond: Hell, Mr. Pierce, we'd be willing to do it for a lot less than ten thousand dollars.
Frank Pierce: If you could! Lomax is the one man that can, so get moving.