RIP for your brothers and all that got F-d by bureaucrats.
Not to disagree but I believe it was the non-spec., high-ash cheap ammo substituted for Vietnam which made the A1 model a POS.
I used a Vietnam-era A1 in training when I first went in. It was fine, jammed once on me from a magazine mis-feed (worn, mushy spring) but was very reliable. We were told the ammo in Vietnam was shit and it got a lot of ppl killed. Still had to clean the F out of those things every time they left the armory.
Liked the A1 and the A2. Found out on Range Duty the A2 would hotfire full-auto after a few mags so no issue with not full auto. It had it baked in and would be there when you needed it.
But yeah F those contractors for swapping in S ammo for profit. CID and FBI should have been all over that.
In my experience an AR will run dirty but won’t run dry.