My buddy had north of 125,000 rounds through his before we swapped the barrel. It was only ever shot at about 10y so that's why it took so long to notice the key holing.
Having said that, its been through a new fcg, 2 buffer springs, 3 cam pins, half a dozen bolts, 4 extractors, 2 gas tubes, 1 gas blocks (has an adjustable now), 1 muzzle brake, many sets of gas rings, a dozen hammer/trigger pins, etc.
The upper has some serious bcg scars, and quite the cam pin gouge.
But its easily over 160k rounds now.
Its used for 'new shooter' groups so that's why such the high round count.
It's not pretty but it still goes bang