I have yet another theory for getting a lower standard deviation (SD) on muzzle velocity (MV).

A lot of people weight sort cases. I think that’s a waste of time because of inherent varying densities in the brass, especially in the head stamp area. What you really need to do is volume sort cases (which is what case weight sorters think they’re doing).

My method would plug the primer hole, place the empty, unprimmed but otherwise fully prepared case on a scale, tare to zero and fill it with a fluid (TBD but probably paint thinner because it’s less dense than water, has less capillary action than water and would evaporate quickly after being blown out). By taring the plugged case to zero (0), the reading would be the weight of just the liquid, and hence the volume. Filling the case would be much like measuring powder. You could use an eye dropper for the initial squirt, then trickle liquid until it came to the top without spilling over.

And please, no environmental whacko comments about the inherent dangers of using paint thinner. Life is full of risks.