One of the soldiers said he fired off 500 rounds continuously until the barrel malfunctioned. That is far too much. At 90 rounds, the barrel steams off all the lube and you are dry firing after that.
Being patient, waiting for a target, pacing your weapon is damn hard to do. But the alternative is no weapon and no ammo and an enemy that knows your weapon is down....
One word, training. If there’s enough training and enough good platoon sergeants to smack people upside the head that are spraying and praying, you can solve this problem to a large extent. Unless you have a couple thousand Taliban badguys making a full frontal charge, there is no need to discard fire discipline.