Visible crew/equipment: In the scene where Laura is being attacked in the desert, the camera swings wildly. During this swing, the entire crew becomes visable for a split second. You can see Clint Eastwood (who also starred in the film) sitting in his director's chair, wearing a white t-shirt and watching the filming closely. (01:19:54)
Visible crew/equipment: The shadows of the camera, crew, and film equipment are visible several times in the sequence when Clint is riding into the Native American camp and the two men are buried up to their heads. The equipment is most visible in the scenes when the sun is facing the Native Americans.
Visible crew/equipment: Just as Sondra Locke is about to have her shirt ripped off by the Comancheros you can see at the top of the sand-dune/hill behind the men, (in the background), a yellow digger. (01:19:27)
Answer: At first, the story advances very rapidly, essentially giving the audience a primer lesson on Josey's angry motivation; so, many minute details aren't explored, such as where he acquired his ammunition. We might conjecture that Josey had a separate out-building, called a "powder house" (which was common in that era) where gunpowder and shot was kept for safety reasons. If he did, that raises the question of why the raiders didn't ransack and burn his powder house as well.
Charles Austin Miller