What was that link to the guy who sells old field and technical manuals here in the U.S.??? I am looking for repros of the manuals on old U.S. pre-First World Artillery pieces.
That would definitely be a nice resource, but there seems to have been a mention and a link here earlier to someone here in the States who sells repro. tech. manuals on pre-First World War and inter-War U.S. military equipment, especially the more obscure artillery pieces, such as the U.S. 6 inch M-1908 field howitzer, 5 inch M-1898 siege etc... Does anyone remember who he is?
Haven't come across that link but is http://www.military-info.com/Index.htm any use? Note some of the materials available there may also be free in digital format elsewhere (such as in the obsolete US manuals indicated by Michel - which are not confined to purely US subjects, by the way). I think you would need to contact them with specific requirements, there would be much content detail there that is not addressed by index title alone.
They also have a page of further links which might be useful: