Yes it gives the longitude. But it doesn't say (I don't read Italian) how far off to either side of the longitudinal line 50% of the shots fall. I called it "vertical" dispersion but should have said horizontal. I'll edit my reply."Disp. long.": dispersione longitudinale = dispersion in length
Thanks for the info on the book.By the way, the source of the table about the 320 and 381 guns has been translated into English:
It is a book which I highly recommend.
Thus, in this 320mm gun test, the shells landed in a roughly 700 meter diameter circle with 2.6% hits. That's about a 1% chance of hitting a nonmoving destroyer, 2.6% on a light cruiser, and 4.7% on a battleship.