Here are four photos to show the work that I've done recently on this project:

The photo above shows the holes drilled for the extractor stem and the guide rod, and the mortise machined into the rear face of the barrels to receive the extractor.

Here is the same view with the extractor fitted into place and the chambers and throats finished to full depth.

This photo shows the top rib finally fitted into place. In my experience, this is always the most labour-intensive part of these conversions. It requires many hours of smoking and filing to get a proper fit between the underside of the quarter rib area and the rapidly changing compound curves in the last 6"-7" of barrels and mono-block. The two screws anchor the rib very solidly and make the final soldering assembly much easier. The rear screw will be hidden under the rear scope base. The front screw will be hidden under the iron sight. The quarter rib and the front sight ramp will be milled down to less than half this height after things are soldered together.

This photo shows the small block that I filed up and had welded into place behind the forend hanger. This block was drilled and tapped 8-40 to accept the forward anchor screw in the top rib. I also filed up the short section of rear bottom rib and had it welded into place at the same time. I've done some work today, first with my Dremel Tool, then with polishing stones, to dress down the welds and even the area out. Still some final polishing required in this area, after soldering the ribs on, before bluing.