I have found a lot of interesting books and here is some of their military manuals. Internet Archive Search: collection:military-manuals
Here are a couple more good ones: Army Field Manuals US Military Manual Collection : Free Texts : Download & Streaming : Internet Archive
I love OLD Military manuals, pretty fascinating and historical details! My all time Favorite is the 1865 Army Field Manual, What a wealth of information contained with in, things every Fellow Monkey should know!!! Something I highly recommend every one should have a copy in there reading collection!