I'll be ordering a Manson Reamer for this project, and I want to avoid the long throat that seems to plague every factory gun. Maybe it really isn't that big of an issue, but based on some of my measurements, the free bore could be shortened by about 0.040" and still allow the use of the entire mag box length.
Shortening the free bore would also allow cast bullets to be seated out in order to mate with the leade (and still have some shank in the neck). If it isn't shortened, there will be quite a jump, which I think would work against accuracy with cast bullets (maybe jacketed too).
Am I over thinking this?