As part of researching my Western novel, I spent a lot of time looking into the activities of the US Army on the post-Civil-War frontier. It features in my first book in that genre, and will play a larger one in subsequent volumes, if I'm spared to write them.
I thought you might like to learn something about the US Cavalry on the plains. This short video documentary doesn't go into a lot of detail, but it's pretty accurate.
Under the circumstances, it's astonishing that the cavalry achieved so much!