Thanks 458Win for the photo update. The amount of opening up to the front feed ramp is virtually identical as mine but I wonder why so much was milled out from the top of the receiver ring and the charger clip guides milled away completely. Mine as you can see in the photos below has not been touched in these ares and has no problem loading cartridges into the magazine from the top or ejecting empty cases.

I have often wondered what effect on the strength of the bolt lock up the fairly severe milling away of the feed ramp/bottom lug area has when looking at my rifle but it seems this is the common way of opening up the standard action. My comfort has always been that the top bolt lug recess quite massive and full strenth.
The action shown by Casper50 is the same in the feed ramp work. I also have some photos of a Win M70 opened up and the same method has been used with a lot taken off the feed ramp.

I wonder just how Rigby (or someone) opened up the standard M98 to fit the 416 Rigby cartridge as they did for Harry Selby's rather famous rifle?

Type A Oberndorf Mauser opened up for the 404J