The chart is in the Member Resources area, under "Gauge/Caliber - Balls per pound".
You need to interpolate between the listings, but it says there are 29 .54 cal balls/pound and 37 .50 cal balls/pound.
However, I shoot a .535 rb in my .54 cal rifles, and that would mean there are 30 rb's/lb in ".54" cal. And I use a .495 rb in my .50 cal rifles, which means there are 38 rb's/lb in ".50" cal.