There have been a few types of military and other agency manuals published on cryptome.org....
As far as manuals on equipment and weapons, I havn't yet seen any , at least not lately..
I actually bought a bunch of army manuals off of amazon for about five dollars apiece. Everything from survival to improvised munitions. I have them
in my BOB/INCH/GOOD bags. I believe the sellers name was greatbookfinder.
US Armed Forces manuals are widly avalable in PDF format online just do some serching, I just the other day downloaded about 1 gig in Army & Marine
field manuals, plus what I have left over form my army days I should have all I need, Survival, Bobby traps, wepons
You can also find some on Google Books (as well as a WEALTH of other full download PDF's of old homesteading type books). Goto Google Books, type in
'field manual' (or other search terms such as "yeast"), then click "Full View", click on your target, look for "PDF" in the upper right
corner. Download and enjoy.