The Making of America page has scanned the Ordnance manual for 1866 into their site. You can look at the Table of Contents for the pertinent pages and download them as html, pdf or txt files. The address is:
http://www.hti.umich.edu/cgi/t/text/text-idx?sid=a1f84c958e744095c3ca299280f619b3&c=moa&idno=AAN0444.0001.001&view=toc
If this doesn't work just do a search for "Making of America" in a search engine - be sure you choose the University of Michigan site, and once there search their listings under books - author United States Navy Dept Bureau of Ordnance.
If it is important for you to have earlier ordnance manuals I do have copies of the Edward Simpson volume (1860-1) around here somewhere. Perhaps I can get its information to you (scanned or transcribed).
Regards.