One thing I forgot to mention, the Archives also has some of the "most frequently requested" information available in publications. One that I ordered and found very interesting is "Ordnance in the Hands of Troops," on one microfilm roll known as M1281, I think. The print on it is very tiny, but most people can read it somehowm on the proper type of machine, of course. It was not expensive back when I got mine maybe 10 years ago, and hopefully it is still available.

It is mostly for the CW period as I recall, and has huge tables by military unit and time period, showing how many of what model of weapons were in the hands of the various units. I think that during the CW, these tables would have been compiled from "ordnance returns" sent in from the field.