How many rounds of 9mm can you put through a Glock 17 before the polymer components literally start to melt?
Well, if you’re talking semi-auto fire, like the Glock was designed for, no human will ever get to the melting point.
However, the guys at IV8888.com set out to see just what it would take to melt a G17. They got a specially modified Gen 3 Glock 17 from Quiet Riot Firearms that has been legally modified with a full-auto sear and shoulder stock. They also got a pile of extended magazines, and they needed them.
As predicted at the beginning of the video, the pistol’s polymer mainspring guide rod was the weakest point. It picked up a lot of transferred heat from the barrel and melted into a plasticky mess after about three minutes of continuous, full-auto fire.
But since they were expecting it, they dunked the gun in water and managed to replace the melted polymer rod with a steel guide rod, and kept on shooting.
The gun kept on running magazine after magazine, until the polymer frame beneath the barrel began to sag from the heat. But after the gun was disassembled, it was revealed that this wasn’t the cause of the gun’s eventual failure.
The control arm on the full-auto sear snapped off, which is why the guns topped running. The slide is pretty much fine to use, accept for the tritium insert in the front sight, which melted. The barrel experienced some rifling stripping at the muzzle and chamber ends.