If your pin is dead on at 20 yd, probably it will be good for all hunting distances out to about 25. That's just a general statement, however; they all are unique. Lots of practice and experimentation will give you a clear idea of what your own bow is capable of.

Stalkingbear, you're sure right about them long shots. As for 100 yards, not only is the KE way down by then, it would take a full second for an arrow to arrive at the target even if it could maintain 300 fps all the way there. That's way enough time for the animal to move significantly and result in a lousy hit.