Hi George,
I get tickled reading about this topic from those that have never served but are experts on military subjects. I served in Vietnam in the field 7 out of 8 months, in country and the rest of my tour of duty in an Army Hospital in Japan as a result of injuries suffered in combat. And, no, I am not a "wanna Be" veteran, my 40% disability says so. I was a Marine "Nail Grunt" where most of the duties were road clearing operations or mine (IED) sweeps, back in the day. Our Battalion took more casualties than any other Marine Engineering unit in the war.
Marines made up only 10% of personnel in country at any given time, but took 25% of the casualties or 1 in 4 names on the wall. That's 2 1/2 times our numbers.
As a small force, we never had enough supplies which included clothing, ammunition and c-rations. We got what we needed by trading captured enemy equipment to the Army or Seabees, so the supply system never reached us or most Marines in general, including our Grunts. We all bought boots and other needed supplies from the local Vietnamese. Give them 5 bucks and your shoe size and presto, you got your new jungle boots the next day at the ville.. Machine gun parts, 105mm howitzers parts and grenades were very hard to get. Try manning an M-60 machine gun with no trigger parts, in a combat zone, and that will tighten up some private body parts. In general, the supply system failed us or the stuff we needed was sold or stolen off the DaNang docks.
I had occasion to later speak to a U.S. Senator about the supply problems and as fate would have it, he launched a Congressional investigation. Hell, I even had my Brother and Father ship me a surplus rain poncho from the States. My flack jacket had the fiber glass panels falling out and I'm in the bush!
I carried the M-14 and the new M-16s were just being issues to the Grunts. From the early reports, the new black rifles were not reliable and several Grunts wanted my rifle in a direct swap. No could do since the rifle was checked out to me. We did not like using AK-47s since their distinct report might bring down friendly fire on us. Still, it was a reliable and respected enemy weapon.
I now have an AK47 and an AR15 carbine, used for fun only, thank goodness. I don't dislike REMFs, but we had to use our wits to survive in the field.