The cocking piece is not held far enough to the rear, by the sear. The safety is hitting the round part of the cocking piece and not engaging the cam on the cocking piece. You'd have to over cut a bunch to hurt firing pin distance. You'd have to over cut a bunch on the sear (or the cocking piece where it engages the sear) to cause 'timing' issues. It's slow work fitting a safety on a Win 70, or any 2 or 3 position firing pin safety on any make or model.In the OP’s case, the safety cannot be engaged because the cocking piece is not held far enough to the rear, by the sear, right?
(Reread your post) OK, yea, my words were jumbled in my first post, thanks for the correction. Over fitting causes the firing pin stroke to shorten, right? Do you run out of firing cocking distance or cause a different timing issue first?