Tom, I think the bevel is designed to fit the extraction groove, not necessarily to provide a cam to snap over.

I believe you are correct about the "no way" part of some 98's not snapping over at all tho, as I think the extractor as mentioned above can't move out enough to snap over in some unmodified 98's.

Putting pressure on my 550 as per RLI's suggestion causes the extractor to easily snap over the rim. On my FN98 it takes quite a bit of hard pressure, and my M46/96 Swede snaps over by itself.