The Military did acquire a few thousand Remington Model 10 shotguns during WWI. Most of them were trench guns. I don't beleive they were used much after WWI, and they certainly would have been disposed of before the Vietnam War. IIRC, the serial number range of these WWI Model 10s were well into the 100,000 range (I think in the 150,000 - 160,000 range).