Quote Originally Posted by darkker View Post
You got lost in the theory there Chukarmandoo, assuming you are actually looking at volume; what you are doing isn't volume, its still weight. If you want to use a volume device for a weight, then you seem to have found a good enough method. If you want to use it as intended, then here are some thoughts.

1 - Indeed :)
2 - Almost, not that it CAN, but that it DOES change.
3 - Charts are nice, but remember #2 just above. Do your own VMD for EACH bottle of powder. The weight portion is to establish a reference point only, VERY few powders will list their nonimal variances for BD, so there is no "right or wrong".
4 - Doesn't matter as long as however you do it, you always always do it the same.
5 - I agree, but the main take home point should be consistency.
6 - Unless they changed it, there is no rubber wiper, it is all just plastic. And cutting extruded kernels doesn't matter, as it is the relative geometry(including perforations) that controls the burning rate. The total area will change when you cut kernels, but not the relative geometry.
7 - Again, if this is about getting to a weight, fine and dandy. But that is incorrect if you actually want to load by volume.

Remember that 99% of the powders you buy do not list nonimal variances(BR & BD). Extruded powder has it's burning rate controlled by geometry, it's weight is only a function of the total energy(BD). The weight taken off of a sample of charge volumes is for a reference point ONLY, it isn't a hard and fast reference point. If you want a more consistent result (from extruded powder only) from your reloads, then you need to control the burning rate. Weight will not do this, only controlling the volume will. A controlled volume in the case fill will also negate burning rate shifts because of differing case volumes. Weight alone only controls the total energy content in the extruded powder, it does not control how quickly it burns, and thus the pressures encountered.
seems to me that weight would vary in a certain volume of powder according to the density of the powder contained in your volume measure. A perfect example is dumping a charge into a case with a short drop tube and a long drop tube. Another example is throwing a charge into a case and then tapping it a few times.

If you are using volumetric measure how do you take the variations in densities between loads into account. In the two examples above the volumes would be quite different but the weight would remain the same.