I don't know if you intended to post the scan of your grandfather's "military notebook" for all to see, but I'm very glad that you did. It's a fascinating document. I don't know what a "military notebook" is. Can you--or someone else looking at this thread--tell me what another equivalent or similar term for this document for the military service(s) of another country (especially the U.S.) that might be used to describe this sort of document and what its function was?
Teaneck, New Jersey
P.S. I notice there's another document in the same scan after the military notebook that seems to be an Argentinian record; did your grandfather immigrate to Argentina after he served in the Russian army?