Need help with RG-10 .22short assembly

[Calgunz420]

So I decided to field strip and clean this and I can't seem to get the half-moon shape piece next to the trigger housing back together. Any help please. Located in San Francisco/ peninsula. Tried going online to look for a schematic for it and nothing.

[JAGGUY]

These guys live and breathe SNS. Have a section on RG's too iirc

http://www.bryco-jennings-jimenezarms.com/forum/