That jungle armory pistol looks fairly sophisticated compared to the one my brother in law brought home in 68. The one he has consists of a 30-06 casing drilled out and to hold a 22LR shell. This is wired to wooden handle. He said a couple other GIs and himself were leaning against a building in the shade and this kid that looked to be in his early teens walked up, aimed the "pistol" and him and hit the back end with a rock, piece of pipe or something. The shot wounded the guy next to him.