[C Doyle 88]

With a very fast bow it'll be a very small amount---maybe as little as 1in but if it's all in point wt the farther out you go the the greater the differance because the higher the FOC the more the level in flight changes and yardage suffers

 

[mdmountainman]

How much will 25 grains affect your POI at 40 yards.

http://home.att.net/~sajackson/ballistics.html