I've run over 500 rounds at a time shooting Steel Challenge practice with my Ruger 22/45 and only ever cleaned it with a bore snake. Ran it to 60,000 rounds before even detail stripping, just oiled the bolt.
Problem with a stuck rod is the only way to get the lead out is to melt it with a propane torch.
That amount of lead in that few rounds makes it sounds like Glock missed the geometry for the number of grooves on the G44, by a lot. Like I said earlier, over 500 rounds at a time with my Ruger 22/45 and just a bore snake to clean. Filthy, but no leading.
Hammer forged rifling (polygonal) will lead faster than cut button rifling, but it's the amount of lead buildup in the short time that's concerning.