(Rather than using single shot rifles, arming the men with repeating rifles would have had greater effect.)
That much is true. The single shot Springfield the 7th were using had a tendency to get hot causing the shell casing to get stuck in the breach when trying to eject.
The ammo was copper cased. It stuck. Brass cases did not.
The tribes before this had been trading for Winchester tube fed lever action rifles. Bourke, in the book, ON THE BORDER WITH CROOK states when they got repeating rifles they became “surly.”