I carried a 16A1 from '76 to '83 for Uncle Sugar, from the Arctic Circle to the Mojave Desert. I did pay attention in basic to the DS's about proper care and regular maintenance, but it is impossible, even in peace time, to maintain that type of regimine that the 'experts' say you have to have for a 16 to work right. But, I still personally never had a malfunction with any of the issued rifles I used during my time in service. A few problems with aged magazines did show up, but that is not the rifles fault.
I had the opp to buy a Colt A2 pattern AR in '94 and jumped on it. 20", 1:9, HBAR Match, and have fired it every time Ive gone to the range or gravel pit to shoot, and out on the prairie to reduce the danger of prairie dog over-population and general varmit removal. I have no clue how many rounds I have put down the tube, and don't really want to think about the cost of those rounds. I have had zero, nada, zilch, nyet (for the AK boys), nein, and nix malfunctions with this rifle. One magazine i got at a surplus store went to the recyclers for giving me trouble though.