Dave I have never actually hunted with a PRB and the load I am shooting was developed for Rondy shooting. 60 grains of T7-3f seems pretty skimpy but sure works for Rondy shoots. But, what about hunting? I have a couple of reasons for the 60/70 grain area, 1. do not want to burn up the patch with the heat created by T7 2. I am always worried about shooting a RRB to fast for a 1-48 twist and loose accuracy. 3. the 60/70 grain load is really accurate.

This is a target with velocities - this might help with my question...