I use a volumetric measure with a rotating cutoff plate on the top that has a funnel on the plate. If you use something like this to charge your speed loaders before going to the range or hunting, I see no practical difference between this and using the measure at the range......

When tested, the "ball's measure" generally produced a significantly low charge, only about 1/3 the "Hawken standardcharge", which was 1/2 the weight of the ball. In addition, it was prety much impossible to get anywhere near the same charge twice by pouring the powder into the hand until it covered the ball.