Apparently this particular 1911 was WW2 issued, made it through all the way to the Vietnam War, and then it was captured -- along with its soldier. When that happened, the war hero pistol was converted (probably by the Viet Cong) to 7.62x25 Tokarev! Lordy lordy... never seen that before.
https://www.legacy-collectibles.com/hand-guns/1911-pistols/scarce 1911a1 - vietnam conversion.html
https://www.legacy-collectibles.com/hand-guns/1911-pistols/scarce 1911a1 - vietnam conversion.html