Some of us cheated.....
..........and got "unauthorized" weapons. We would have to turn them in, if we got caught at it.
I bought a 60mm mortar ($50 MPC) (less sights) from the local RF/PF company that my 105mm howitzer battery used for self-illumination purposes. Left it to the MACV advisors when we pulled out and stood down.
I also bought an .45 ACP M-3 "greasegun" for $20.00 from the ARVNs, but obviously I couldn't get this on the plane home and so gave it to one of the guys at II Corps HQ. Damn shame; it had the flash hider, magazine case and 5 mags.
What I really wanted but couldn't find was a .22LR rifle to use in our bunkers against the immense rats (we called them BFRs) that came inside during the monsoon. We finally made a special 45 round by pulling the slug, putting tissue paper over the power, placing an Artillery Plotting Needle in the center and then filling up the remaining space with melted candle wax. We'd field-strip the 1911, carefully ease the needle round into the barrel, then re-assemble the loaded gun. Shoot the rat, and pin it to the bunker wall, then the GI's dogs would get it. Great sport!