When I had the original barrel cut the plan was to match it to factory cases for cast slug shooting (ball/conical). The plastic case ID was something around .625 and I opted for .005 rifling. When I tested the Brenekees, 50 yard accuracy was literally the size of a slug hole. Unfortunately the 2.75 slugs went subsonic and at 100 the group was upwards of 7".
Moved over to the 3" and things improved. The only more accurate slug was the Lightfield, but I have a big supply of the former so that is the one I regulated to.
I do have Ellis Brown's book and it is very helpful. The chart is from the Brownells catalog. It helps with sight heights and is here https://www.brownells.com/.aspx/lid=13093/GunTechdetail/Sight_Correction_Calculator

It did work just like adjusting sights; at least this time.

CC, really like the black locktite fix. I was considering duct tape and posting pix...