A "patterning" board when used to determine the pattern that a particular load gives you out of a particular gun with a particular choke is normally placed at 40 yards.
The board used for determining where a gun is shooting in relation to where you are looking is - as noted - at 16 yards.
Proper gun fit is what makes the gun shoot where you are looking.
There are a lot of people here who know more about it than I.
Pete (15.75" LOP, drop at comb 1.5", at heel 2.5", Cast 3/8"off, Pitch +4)
"Only hunting and mountain climbing are sports. The rest are just games." - R.Ruark
NRA Life Member