The first mention of the 32-70 USN,that I saw,was in the book"Winchester,The Gun That Won The West" by Harold F. Williamson.
It list the cartridge as being loaded in 1893 with smokeless powder.
Winchester supposedly only loaded 2000 rounds for the Navy,I don't know if any of the asenals loaded any.
Physical dimensions are; .554 rim,.478 base,.358 neck,2.53 case length,3.27 o.l.,.328 bullet dia. 235 or 245 gr.full metal jacket.At the same time Winchester was working on a civilian verson known as the .32-80 WCF.
I have been told that it is listed in Hoyem Vol.4 ,page 73 and WRA Headstamped Cartridges And Their Variations by Daniel L. Shuey on page
239. There is also a book, about experimental military cartridges of Frankfort Arsenal,
that may list it bul I'm not sure of the name of the book.
WC