I disassembled my OS 95AX to examine the internals. Everything looks okay. I was wondering about the piston ring and groove. If I slide the ring along its groove I come across what looks like a small set screw (or something - its so small) inside of the piston groove. What is the purpose of this? Is it supposed to hold the ring in place? When I compress the ring the split in the ring grips this "thing" in the groove. Should I reassemble the engine so that the split part of the ring aligns with this thing in the groove? The diagram in the OS manual seems to show something is there in the groove.

Thanks.