Mark, I haven't had the adjustable lump apart but my understanding is that as the eight faceted large set screw is screwed in it bears on an angled 45 degree wedge that pushs down on a similarly angled piece that shows on the photo and moves forward to take up any slack on the hinge pin.The small set screw obviously locks it in place.
Homeless, I believe the forend fastener is a Scott Patent and as you can see there is a small third bite on the dolls head,not sure if it has a name? Anyway, I love my Scotts,they are all serious shooters meant/built to be used and enjoyed,which I do as often as possible.

Better to keep your mouth shut and be thought stupid,than open it and confirm.