Shems like the ones pictured came with my FRANCHI.
With a little trial and error,got the right one installed now. ---- SAWMAN
ADDED: A small amount of cast off to the R,and max drop at the comb seems to put my R eye streight down the somewhat raised rib.
Will most likely end up putting a fiber optic on also. - - -
It's called cast off.
If you look at a fitted high end shotgun, the stock is not aligned straight with the receiver and barrel. Some even have a palm swell in the pistol grip.