Sturgess provides a rather different reason for the rear frame toggle strike mark. He addresses the entire rear frame strengthening process and reasoning in detail on pp1091-1098 of the red edition. In the course of the discussion he notes how and why the rear frame toggle mark is the result only of the toggle tail being levered against the frame during hand-operation of the action; during actual firing the toggle tail does not contact the frame. It is worth taking the time to read.
He does contradict this in passing, in several comments previous to this section.
--Dwight
|