That's great. I have no idea what the U.S. policy was on weaponry issued to troops after they were discharged. I don't know if they even had the opportunity to keep their service weapon, or if they were forced to turn it in. (or "liberate" it?)
With regards to my grandad's weapon- Frank posted the following to me via PM: "I'm thinking it's a Winchester, by the type of handgaurd. Type 1 barrel band, highwood oval cut stock, two rivet bullnose handgaurd."
That's helpful info, and will assist me in narrowing down what my search criteria is.