I tried the heavy black sand in my front bag but replaced it with silica sand. It fills nicely but doesn't get as hard. Before each yardage, I knead the front bag and loosen it up a bit.
A hard/tight front bag can be bad juju for going around a Score target. To shoot Score well, you have to be able to go from any record target...down to the sighter...and back to the record target...with z-e-r-o difference in p.o.i.
But much of this is specific to the shooters entire setup as a whole. The type of stock, how the fore end angle changes in the front bag as you go around the target, etc, etc. all contribute to the whole picture.
For what it's worth............ -Al