John Bivins once told me that in order to get a good pitch on the butt plate when making your pattern so that if you stood your pattern with the heel of the butt against the wall and the butt having full contact resting on the floor the end of the barrel should be 11” away from the wall. Now at that time John was building the Bicentennial rifles with a 44” long barrel. Hope this helps. It did me over the years when I was building. Jerry