Wow, I had missed the G36 story. How in the heck does a major military allow rifle procurement to go that sideways? Hot weather sustained performance is easy to test.
The G36 story is not quite what it seems to be, though. There have been independent tests that show the problem isn’t necessarily the barrel or trunnion or receiver as the German government claims. I’ll link one at the bottom; there seem to be political concerns that make it expedient for the Germans to dump H&K as their official supplier. The replacement is, after all, an H&K design (the 416) just being made by someone else so there’s a layer of plausible deniability.
Mind, the G36 needed to be replaced but not for the reasons the German government stated.
https://www.youtube.com/watch?v=g4StCCv8QW0
https://www.youtube.com/watch?v=MfPHZFsw40M