I have done quite a bit of work with the HB's. They are very individualist as the thickness and volume of the HB determines what pressure is needed to get them to work. Soft alloys, under 10 BHn, need a medium powder in revolvers, while those from WW's, about 12 BHn, need something faster like Bullseye. Use as little crimp as possible for best accuracy. Keep velocity down to about 750 or less in revolvers, and use good lube in rifles as bore friction is high for a long time.
They are used for an expedient for mis-matched throats and barrels, but do make accuracy possible. With some revolvers, that is the only thing that will work.