Good to know bud, good info.
Hmm... Something's odd about that as there's no way the polygonal bore's going through the plating in my mind, AND the gas port's right back at the chamber, so even if it was a conventional barrel which it isn't and the lead was being exposed at all, all that should get leaded is the bore. Plated has always been the
most clean for me as far as the gas cylinder due to a non exposed base.
As well, I just went back to my M8 to try, I think your friend's pulling a fast one on you about the spontaneous disassembly.

You have to not only depress and hold the button, but then pull the slide a half inch to the rear, stop, and pull up then angle the slide over the barrel. If somebody was able to do this unintentionally, they're special.

A Beretta 92 should be just as or more likely to "spontaneously disassemble".