The above extractor link is from my Stevens 235 project gun. I don't have a good one to compare but I'm thinking the now half-moon shape of the button that rides in the frame was once full round. The link slips out of the mortise in the frame and the barrels fall full open without the extractor being lifted.

I can't locate a replacement. Is there a way to refurbish this one?

It looks like the part could be an assembly of the basic flat piece, two cone shaped parts and a pin.