When the trooper runs at the Apaches to throw the third canteen bomb, its fuse is not lit and the explosion occurs in front of him before he lets go of it. Apparently the script just called for him to be killed off somehow, because the other two just threw theirs from the same close distance, while he had to run right into the middle of the Indians to 'throw' his.
The gunpowder bombs supposedly killed "most" of the Apaches, yet they leave in a casual manner as if there are none left. They had no way to know if any were still alive and could have attacked them as they left.
The .45-70 round fired from a Trapdoor Springfield carbine has considerable recoil, yet the troopers fire with no appreciable effect, showing blank rounds were used.
The storm mysteriously disappears just after they throw the gunpowder bombs allowing them to leave in clear weather.
Since the Apaches huddled down during the storm, why did they have to use the gunpowder bombs? They could have just left during the storm without being seen and have had a large lead on the Apaches. Plus the storm would have covered their tracks not allowing the Apaches to find them.
They announce there is not enough water and they will go to rationing. Main character makes a big speech about conserving water and being very thirsty before taking a drink. Next scene, the girl strolls up and hands him a big cup of coffee -- did they make it without water???