I did find some notes on Mauser doing an endurance test with an early Mauser Parabellum. They fired 3000 rounds in succession, using multiple magazines. The pistol was cooled intermittantly in a bucket of water
The gun was ok. Only malfunctions were holdopen fails on empty mags. They did manage to break the bottoms of most magazines. Also the width of the mags changed by .3 mm on average.