here is a enhanced parts list. I circled and marked up what I thought were important piece's. the stubs on pistol and charging attachment appear to need #91 o ring.to seal the cylinder.
I rebuilt the check valve on cylinders. and still has big leak. parts list shows Oring 91 doesnt show location. (7x2mm) it appears the might be a recess for a O ring at bottom. is that O ring needed there?