I was at the range yesterday blasting away with my pistol.  Performed flawlessly as always and fired somewhere between 200-300 rds.  Was firing a lot of different weapons so didn't keep rounds count.  Have never had a malfunction so far with this pistol.

When cleaning it later I found one of the bolt gas rings to be missing part of it and very worn on one side.  The tip of the worn area is bent back slightly so I am wondering if the end of the ring might have caught in one of the gas escape holes in the bolt carrier and ripped the end off.  No scratches or damage in the carrier or on the bolt that I could find.  The bad ring was located in the front of the 3, closest to the bolt head.

Any idea what caused this to happen?  Have fired thousands and thousands of rounds through various AR's and never had this happen.  Gas rings have mostly been a no thinking type part to me, as long as the gaps are spaced properly.  The empties eject to the 4-5 o'clock area so I don't think its overgassed.

Is that worn from the inside or outside? If it were the outside I would say a problem with carrier, but it looks like it's inside wear.

I wouldn't over-analyze it. Replace all three rings & move on.

Yeah thats pretty much the plan.  Hopefully its just a bad gas ring.

If your bcg came assembled from the factory, it may be just a bad ring that made it through QC.

if you use quality ammo, you might try a McFarland style continuous ring... my 16" didn't like them with Wolff