RE: weighing blackpowder charge ?
Yes, I did this when I first started shooting BP in order to determine if there was any measurable difference between measured and weighed charges. I tested the two methods for accuracy (group size) and for variation in muzzle velocities also. I found there is NO statistically significant difference in either performance factor, IF the measured charges are measured in a very uniform way. To do this, I pour the measure full to the top, then tap it five times on the side with the wooden handle of a small screwdriver, refill the meaure back to the top (the powder settles about 0.25" due to tapping), then strike it off flush with a card. Using this method, you can cut powder charge weight variation to less than half a grain for a measured charge.