Military Rank in Letter?

[MacGyver]

Hi,

First off, I'm sorry if I posted in the right place - which I probably did. I have a letter to my Grandfather, and I believe the beginning says something about his military rank. The letter is in Polish (or maybe Russian - I can't read it very well. Handwritten.), but he served in the USA military in WW1. The beginning of the letter says something like this:

Kusovry Pumo [with dash over the O, but it might be an S] M.S.A ___!!!

The blank is my ancestors name. Is M.S.A a military abbreviation? A was his first initial (or so we've been told...), so it might just be M.S. I have no idea. Does this ring a bell for anyone? It may or may not be military, but I don't know what else it would be.

Thanks,

Mac

[lithgow]

Hello-I would try putting the question in the Polish forum as many there are Polish speakers.